NiTi alloy prepared by microwave sintering
Microstructure,mechanical properties and superelasticity of biomedical porous NiTi alloy prepared by microwave sintering
J.L.Xu a ,b ,?,L.Z.Bao a ,A.H.Liu b ,X.J.Jin a ,Y.X.Tong c ,J.M.Luo a ,Z.C.Zhong a ,Y.F.Zheng d ,?
a
School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063,PR China
b
Jiangsu Provincial Key Lab for Interventional Medical Devices,Huaiyin Institute of Technology,Huaian 223003,PR China c
Center for Biomedical Materials and Engineering,Harbin Engineering University,Harbin 150001,PR China d
State Key Laboratory for Turbulence and Complex System and Department of Materials Science and Engineering,College of Engineering,Peking University,Beijing 100871,PR China
a b s t r a c t
a r t i c l e i n f o Article history:
Received 7April 2014
Received in revised form 8October 2014Accepted 21October 2014
Available online 23October 2014Keywords:
Porous NiTi alloy Microwave sintering Superelasticity Porosity
Mechanical properties
Porous NiTi alloys were prepared by microwave sintering using ammonium hydrogen carbonate (NH 4HCO 3)as the space holder agent to adjust the porosity in the range of 22–62%.The effects of porosities on the microstruc-ture,hardness,compressive strength,bending strength,elastic modulus,phase transformation temperature and superelasticity of the porous NiTi alloys were investigated.The results showed that the porosities and average pore sizes of the porous NiTi alloys increased with increasing the contents of NH 4HCO 3.The porous NiTi alloys consisted of nearly single NiTi phase,with a very small amount of two secondary phases (Ni 3Ti,NiTi 2)when the porosities are lower than 50%.The amount of Ni 3Ti and NiTi 2phases increased with further increasing of the porosity proportion.The porosities had few effects on the phase transformation temperatures of the porous NiTi alloys.By increasing the porosities,all of the hardness,compressive strength,elastic modulus,bending strength and superelasticity of the porous NiTi alloys decreased.However,the compressive strength and bending strength were higher or close to those of natural bone and the elastic modulus was close to the natural bone.The superelastic recovery strain of the trained porous NiTi alloys could reach between 3.1and 4.7%at the pre-strain of 5%,even if the porosity was up to 62%.Moreover,partial shape memory effect was observed for all porosity levels under the experiment conditions.Therefore,the microwave sintered porous NiTi alloys could be a promising can-didate for bone implant.
?2014Elsevier B.V.All rights reserved.
1.Introduction
In the past few decades,nearly equiatomic nickel –titanium alloys (NiTi,nitinol)have been considered as excellent biomaterials with poten-tial use in human hard tissue repair and replacement due to their unique properties,such as shape memory effect,superelasticity,good impact resistance and damping,high corrosion resistance and excellent biocom-patibility [1–4].However,one of the most critical issues frequently en-countered in hard tissue replacement applications is “stress shielding ”generated from the large mismatch of elastic modulus between the hard tissue (b 20GPa)and the implant materials (N 100GPa),which may lead to the resorption of the hard tissue,loosening of the implants and ?nally,the failure of implantation [5–7].To solve this problem,intro-ducing pores into the bulk materials and forming the porous materials are the most ef ?cient methods except for developing new lower elastic mod-ulus biomaterials [8–13].Porous structure could not only provide the ad-justable elastic modulus and improve the biomechanical compatibility of the implants,but also allow the ingrowth of new bone tissue and vascu-larization and a ?rm ?xation of the implants could be obtained.Therefore,
porous NiTi alloys have attracted many attentions as implants for hard tis-sue repair and replacement recently,such as maxillofacial and dental im-plants,cervical and lumbar vertebral replacements,joint replacements,bone plates,bone tissue engineering,spine fracture ?xation,and anchor-age and repair [8,9].
Previously several powder metallurgical methods had been employed to fabricate the porous NiTi alloys,including conventional sintering (CS)[14],hot isostatic pressing (HIP)[15],self-propagating high-temperature synthesis (SHS)[16]and spark plasma sintering (SPS)[17].In recent years microwave sintering technique has emerged as a new sintering method for ceramics,semiconductors,metals and composites [18–20].Microwave sintering is a process described as follows:the materials,coupled with microwaves,absorb the electro-magnetic energy volumetrically,which transforms into heat up to sintering temperature when the densi ?cation and alloying are eventu-ally realized [18,19].As a consequence,compared with conventional sintering,the microwave sintering technique possesses many intrinsic advantages,such as reduced energy consumption,rapid heating rates,reduced sintering times,enhanced element diffusion processes and im-proved physical and mechanical properties of the sintered materials [18,19].Recently,Tang et al.[21]and our preliminary work [22]reported that the porous NiTi alloys could be prepared by microwave sintering,
Materials Science and Engineering C 46(2015)387–393
?Corresponding authors.
E-mail addresses:jlxu@https://www.sodocs.net/doc/998945363.html, (J.L.Xu),yfzheng@https://www.sodocs.net/doc/998945363.html, (Y.F.
Zheng).https://www.sodocs.net/doc/998945363.html,/10.1016/j.msec.2014.10.053
0928-4931/?2014Elsevier B.V.All rights
reserved.
Contents lists available at ScienceDirect
Materials Science and Engineering C
j ou r n a l h o m e p a g e :w ww.e l s e v i e r.c om /l o c a t e /ms e c
but the sintered porous NiTi alloys exhibited low porosities and irregular pore size as well as containing many undesired secondary phases(Ni3Ti and NiTi2).In this paper,the biomedical porous NiTi alloys possessing different porosities and regular pore sizes with few second phases were prepared by microwave sintering and space holder technique.At the same time,the effects of porosities on the microstructure,mechanical properties,phase transformation temperatures and superelasticity of porous NiTi alloys were also in-vestigated systematically.
2.Material and methods
Commercially available Ni carbonyl powders(particle size~2μm, purity N99.7%)and Ti powders(particle size~10μm,purity N99.9%), with a nominal atomic ratio of50.8to49.2,were used to prepare porous NiTi alloy in this experiment.The?120mesh sieved pure ammonium hydrogen carbonate(NH4HCO3)particles were mixed into the Ni–Ti powders as the space holder agent to adjust the porosities with the con-tents of0,10wt.%,20wt.%,and30wt.%,respectively.The mixed Ni(CO)4-Ti-NH4HCO3powders were blended in a planetary ball mill (QM-3SP4,Nanjing University Instrument Plant)at the speed of 200r/min for2h.The blended powders were cold-pressed into green samples(Ф20mm×15mm and6mm×6mm×50mm)through a uni-axial pressure of260MPa for30s.The green compact samples were put into an alumina crucible with SiC particles covering the green sample. Then the alumina crucible was put inside a mullite?ber cotton insulation barrel.The schematic diagram of the insulation barrel setup is shown in Fig.1.Finally,the insulation barrel was put into a2.45GHz5kW contin-uously adjustable microwave equipment(NJZ4-3,Nanjing Juequan co., Ltd.).The green compact samples were sintered by microwave heating at a rate of20–30°C/min to1000°C for15min.During the sintering pro-cess,the microwave sintering chamber was?lled with high purity argon gas?ow(99.999%)and a Reytek infrared pyrometer was used to measure the temperature of the sintered samples.
The porous structure of the porous NiTi alloys was investigated by an optical microscope(DM1500,Shenzhen Hipower).The average pore sizes of the porous samples were analyzed by the software of image-pro-plus6.0and the general porosity(P)was tested by Archimedes drainage method,calculated by the following formula:
P?1–ρ=ρ0
eTe1T
whereρandρ0represent the density of the sintered porous NiTi alloy and the theoretical density of solid NiTi alloy,respectively;ρ/ρ0is the relative density.In this experiment,the theoretical density(ρ0)was 6.45g/cm3[23].
The phase composition of the porous NiTi alloys was identi?ed by X-ray diffraction(XRD,Bruker D8FOCUS).The phase transformation behavior of the porous NiTi alloys was characterized by using a Perkin-Elmer Diamond differential scanning calorimeter(DSC)with a heating/ cooling rate of20°C/min,and the phase transformation temperatures extracted from DSC curves were obtained by tangent method using Pyris software.Rockwell hardness of the porous NiTi alloys was measured by HRB-150A Hardness tester with a load of100kg https://www.sodocs.net/doc/998945363.html,pression test was carried out at an ambient temperature of25°C with a constant rate of0.05mm/min on Instron WDW-50testing machine to obtain the compressive strength and elastic modulus of the porous NiTi alloys and with a constant rate of0.5%/min on Instron3365testing machine to in-vestigate the superelasticity of the porous NiTi alloys.At the same time, the three loading–unloading cycle compressive tests under the pre-strain of5%were carried out(the different pre-strains had been tried, but5%of the pre-strain was the best to distinguish the superelastic behav-ior of the porous NiTi alloys with different porosities).The compressive samples were machined into a cylindrical solid with a dimension ofФ5mm×10mm(L/D=2.0,ASTM E9-09).The bending tests of the rect-angular porous NiTi alloys(5mm×5mm×45mm)were carried out at ambient temperature of25°C with a constant rate of0.05mm/min on Instron WDW-50testing machine.The bending strength(σf)of the porous NiTi alloys could be calculated by the following formula:
σf?3FL=2bh2
where F is the maximum loading during testing procedure,L is the span between two supports and b and h represent the breadth and height of the samples,respectively.In this test,the span L was30mm.
3.Results and discussion
Fig.2shows the optical micrographs of the porous NiTi alloys prepared by microwave sintering with different contents of NH4HCO3.It could be seen that the number of pores distributed over the surface of the porous NiTi alloys increased with increasing the contents of NH4HCO3.The pores of the porous NiTi alloys without adding NH4HCO3 were isolated and the connectivity among the pores was gradually en-hanced as the increase of the NH4HCO3contents.The average pore sizes of the porous NiTi alloys also increased with increasing the contents of NH4HCO3,shown in Fig.3.The average pore size of the porous NiTi alloy without adding NH4HCO3was only26μm,while it increased from 120μm to178μm with increasing the NH4HCO3contents from10wt.% to30wt.%.Especially,the pore size of the sample prepared with10% NH4HCO3(120μm)was consistent with the size of the sieved NH4HCO3 particles(?120mesh,~125μm).There existed a geometrical heredity effect of space-holder NH4HCO3particles on the pore shape and size of the porous NiTi alloys[24].By further increasing the contents of NH4HCO3,the number of pores increased and some of them might con-nect together,resulting in the increase of the pore sizes,even higher than the size of NH4HCO3particles.
The porosities and densities of the porous NiTi alloys prepared by microwave sintering with different NH4HCO3contents are shown in Fig.4.The porosities of the porous NiTi alloys increased with increasing the contents of NH4HCO3,while the densities decreased.The porosity of the porous NiTi samples without adding NH4HCO3was only22%,and it increased from41%for10wt.%NH4HCO3sample to62%for30wt.% NH4HCO3sample.On the other hand,the density decreased from 5.03g/cm3(0NH4HCO3sample)to2.41g/cm3(30wt.%NH4HCO3 sample),which was lower than those of aluminum and its alloys (~2.7g/cm3)and very close to the density of human bone(1.8–2.1g/cm3)[25].According to the references[26,27],the ideal bone implant materials should have the porosity in the range of30–90% and the optimal pore size of100–400μm.Therefore,the porous NiTi alloy fabricated by microwave sintering had suitable porosity and pore size to become a promising candidate for bone
implant.
Fig.1.Schematic diagram of the insulation barrel setup.
388J.L.Xu et al./Materials Science and Engineering C46(2015)387–393
Fig.5shows the XRD patterns of the porous NiTi alloys prepared by microwave sintering with different porosities.The porous NiTi alloys consisted of nearly single B2NiTi phase with few other impurity phases as the porosities lower than 50%,while the diffraction peaks of the un-desired secondary phases Ni 3Ti and NiTi 2increased by further increas-ing the porosities.The microwave sintering process,including the greatly enhanced diffusion of the atoms under the microwave ?eld and the quickly derived microwave heating from absorbing the electro-magnetic energy volumetrically (which were fundamentally different from the conventional heating derived from the conduction,radiation and convection)[18,19],could accelerate the alloying of the NiTi green compact sample and facilitate its complete reaction,resulting in the formation of nearly single NiTi phase with few secondary phases.After the thermal decomposition of NH 4HCO 3occurred,the excessive pores were left inside the NiTi green compact sample,which would im-pede the diffusion of the atoms on a large scale and form the local Ti-rich region and Ni-rich region,resulting in the increase of Ni 3Ti phase and NiTi 2phase as the porosities higher than 50%.However,the weak dif-fraction intensity of the Ni 3Ti and NiTi 2indicated that their contents inside the porous NiTi alloys were limited,much lower than other porous NiTi alloy prepared in the previous references [21–23,28,29].It is dif ?cult to obtain single NiTi phase for porous NiTi alloy prepared through one-step powder metallurgy methods including CS,HIP,SHS and SPS [8,30,31].Therefore,it can be concluded that the microwave sintering method is bene ?cial to reduce,even eliminate the secondary phases (Ni 3Ti and NiTi 2)for the preparation of porous NiTi alloys,which can improve the thermomechanical properties,corrosion resis-tance and biocompatibility of the porous NiTi alloys [32–34].
Fig.6shows the effect of porosities on Rockwell hardness of the po-rous NiTi alloys.The Rockwell hardness of the porous NiTi alloys abrupt-ly decreased by increasing the porosities,meanwhile its standard deviation gradually increased.The hardness of sample with porosity of 22%could reach 66HRB,while it decreased by 71%for the sample poros-ity of 62%(19HRB).The increase of porosities resulted in the decrease of the support force of pore walls,which inevitably decreased the hardness of the samples.
The compressive stress –strain curves of the porous NiTi alloys with different porosities are shown in Fig.7and the compressive
strength
Fig.2.Optical micrographs of the porous NiTi alloys prepared by microwave sintering with different contents of NH 4HCO 3:(a)0;(b)10wt.%;(c)20wt.%;and (d)30
wt.%.
Fig.3.The average pore sizes of the porous NiTi alloys prepared by microwave sintering with different NH 4HCO 3
contents.Fig.4.The porosities and densities of the porous NiTi alloys prepared by microwave sintering with different NH 4HCO 3contents.
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and elastic modulus of the porous NiTi alloys extracted from the stress –strain curves are shown in Fig.8.An initial stage with low slope ap-peared in the compressive curves that may be related to experimental instrument and procedure error.By ignoring the initial stage,it could be seen from Fig.7that the compressive process could be divided into three regions as follows [35]:(1)a linear elastic deformation region,where the slope could be considered as the elastic modulus of the sample;(2)a plastic yield deformation region,where a peak stress ap-peared,considered as the compressive strength of the sample;and (3)a densi ?cation and rupture region,where the walls of the pores would collapse and the rupture of samples has occurred.It could be clear that the compressive strength and elastic modulus of the porous NiTi alloys decreased by increasing the porosities.The compressive strength and elastic modulus of the sample with porosity of 22%could reach 880MPa and 7.5GPa,respectively.By increasing the porosities,they decreased from 319MPa and 3.91GPa for the sample with porosity of 41%to 69MPa and 1.1GPa for the sample with porosity of 62%,respectively.The elastic modulus of the porous NiTi alloys which ranged from 7.5GPa to 1.1GPa was very close to the elastic modulus of natural bone (3–20GPa for cortical bone and 0.05–0.5GPa for cancellous bone)[36].The compressive strength of the porous NiTi alloys which ranged from 880MPa to 69MPa was higher or close to the compressive strength of natural bone (100–230MPa for cortical bone and 2–12MPa for cancel-lous bone)[36].
The bending strength is another important mechanical property for the bone implant materials besides the compressive strength and elastic modulus.The bending strength of the porous NiTi alloys with different porosities is shown in Fig.9.The bending strength of the porous NiTi
alloys almost linearly decreased from 371.4MPa for the sample with porosity of 22%to 74.0MPa for the sample with porosity of 62%by increasing the porosities,all of which was higher or close to the bending strength of natural cortical bone (50~150MPa)[36].Therefore,by only considering the compressive strength,elastic modulus and bending strength,the porous NiTi alloy fabricated by microwave sintering could be a promising candidate for the hard tissue repair and replace-ment implant.
The effect of porosities on the phase transformation behavior of the porous NiTi alloys is shown in Fig.10and the phase transformation tem-peratures are listed in Table 1.Two exothermic peaks were observed during the cooling process,in which the transformations of B2phase to R phase and R phase to B19′phase might occur.On the other hand,only one endothermic peak was detected during the heating process,in which B19′phase transformed into B2phase.This result was consis-tent with the reference [21,23].According to the DSC curves and Table 1,it was clear that the porosities had few effects on the phase transforma-tion temperatures of the porous NiTi alloys.In general,the phase trans-formation behavior of the dense NiTi alloys mainly depends on the alloy composition and heat treatment process.In this paper,the composition and heat treatment process of the porous NiTi alloys with different po-rosities were the same.Therefore,they had the same phase transforma-tion behavior and the same transformation temperatures.On the other hand,the porosities had few effects on the phase transformation tem-peratures of the porous NiTi alloys.
The stress –strain curves of loading –unloading compressive tests of the porous NiTi alloy with different porosities at pre-strain of 5%are shown in Fig.11and the experimental results are shown in Table 2.
It
Fig.5.XRD patterns of the porous NiTi alloys prepared by microwave sintering with different
porosities.
Fig.6.Rockwell hardness of the porous NiTi alloys with different porosities for 100
kgf.
https://www.sodocs.net/doc/998945363.html,pressive stress –strain curves of the porous NiTi alloys with different
porosities.
Fig.8.Relationship between porosity and compressive strength and elastic modulus of the porous NiTi alloys.
390J.L.Xu et al./Materials Science and Engineering C 46(2015)387–393
could be seen that the maximum stress and superelastic recovery strains of the porous NiTi alloys decreased by increasing the porosities,while the residual strains increased.Each sample was compressed to the strain of 5%at room temperature,and was then unloaded.After unloading,the residual strains were 0.44%,1.65%,1.84%and 2.72%for the samples with porosity of 22%,41%,50%and 62%,respectively.On the other hand,the superelastic recovery strains of the samples could be up to 4.56%,3.35%,3.16%and 2.28%,respectively.If the compressed samples were heated to 80°C,higher than the A f ,the residual strains of the samples could be recovered to 100%,75.1%,63.2%and 37.7%,re-spectively due to their shape memory effect,which formed the memory
recovery https://www.sodocs.net/doc/998945363.html,stly,the total of strain recovery of the porous NiTi al-loys,including superelastic recovery strains and memory recovery strains,could be obtained and shown in Table 2.The strain recovery of the porous NiTi alloys also decreased by increasing the porosities.
In order to investigate the effect of training on the superelasticity of the porous NiTi alloys,three loading –unloading cycles were carried out.The cycling stress –strain curves of the porous NiTi alloys with different porosities are shown in Fig.12.After three loading –unloading cycles,all of the stress –strain curves turned into closed loops,in other words,the samples exhibited nearly complete superelasticity.The superelastic re-covery strains of the porous NiTi alloys could reach 4.7%,4.4%,4.0%and 3.1%for the samples with the porosity of 22%,41%,50%and 62%,re-spectively.The results were higher than those of the above-mentioned values,indicating that training could greatly improve the superelasticity of the porous NiTi alloy,consistent with other references [21,37].How-ever,the superelasticity of the trained porous NiTi alloys was also lower than the pre-strain of 5%.It is well known that the dense bulk NiTi alloy can recover up to 8%strain in uniaxial deformation by a reversible stress-induced martensitic transformation [1,2].However,when the po-rous NiTi alloy was deformed to 5%,the certain local strain might be higher than 8%due to the stress concentration generated from the large number of pores or other defects inside the porous NiTi alloy.Therefore,the porous NiTi alloy is dif ?cult to possess the actually com-plete superelasticity or shape memory effect even with training.
The porous NiTi alloys exhibiting excellent superelasticity (N 3%)can greatly match the natural bone which has a recoverable strain around 2%[1,4,37].This mechanical characteristic of the porous NiTi alloy is incomparable for other metallic biomaterials,such as Ti,Ti –6Al –4V,stainless steels,and Co based alloys.Moreover,the unique property should obtain easier deployment of porous NiTi into the implantation site.With the combination of the porosity,pore size,relatively pure phase composition,mechanical properties,shape memory effect and superelasticity,it could be concluded that the porous NiTi alloys pre-pared by microwave sintering using ammonium hydrogen carbonate as the space holder agent should become a promising candidate for bone
implant.
Fig.9.Relationship between porosity and bending strength of the porous NiTi
alloys.
Fig.10.DSC curves of the porous NiTi alloys with different porosities:(a)heating and (b)cooling.Table 1
Phase transformation temperatures of the porous NiTi alloys with different porosity.Porosity (%)
Cooling process Heating process R s (°C)
R f (°C)M s (°C)M f (°C)A s (°C)A f (°C)2218.07.37.1?9.043.449.84120.17.97.2?9.143.450.75021.47.77.5?8.540.250.862
19.4
7.6
7.5
?7.5
42.1
50.6
Fig.11.Stress –strain curves of loading –unloading compressive tests of the porous NiTi alloy with different porosities at the pre-strain of 5%.
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4.Conclusions
(1)Porous NiTi alloys were successfully prepared by microwave
sintering and space holder technique.The porosities of the po-rous NiTi alloys increased from 22%to 62%by increasing the con-tents of NH 4HCO 3and the corresponding average pore size increased from 26μm to 178μm.
(2)The porous NiTi alloys consisted of nearly single NiTi phase with
few secondary phases as the porosities lower than 50%,while the Ni 3Ti phase and NiTi 2phase increased by further increasing the porosities.
(3)The porosities had few effects on the phase transformation tem-peratures of the porous NiTi alloys.Partial shape memory effect was observed for all porosity levels and the porosities had ad-verse effect on the shape recovery.
(4)By increasing the porosities,all of the hardness,compressive
strength,elastic modulus,bending strength and superelasticity of the porous NiTi alloys decreased.The superelasticity of the po-rous NiTi alloys could be improved through training.
Acknowledgments
The authors gratefully acknowledge the ?nancial support of the project from the National Natural Science Foundation of China (51101085),the National Natural Science Foundation of Jiangxi Province (20114BAB216014),the Foundation of Jiangsu Provincial Key Laboratory for Interventional Medical Devices (JR1416)and the Science and Technology Plan Projects of Jiangsu Province (BE2011726).References
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薄板焊接工艺方法
薄板焊接工艺方法公司内部档案编码：[OPPTR-OPPT28-OPPTL98-OPPNN08]
薄板焊接变形控制经验 薄板焊接变形的质量控制包括从钢板切割开始到装夹、点固焊、施焊工艺、焊后处理等，其中还要考虑所采用的焊接方法、有效地变形控制措施。 1、焊接方法对焊接变形的影响* 合适的焊接方法需要考虑生产效率和焊接质量，所以焊接方法、焊接工艺和焊接程序显著影响焊接变形的水平。因此所采用的焊接方法必须具有高的熔敷效率和尽量少的焊道。7 R" F: v" @, `8 H5 C7 N 尽可能减少不必要的焊缝； 合理安排焊缝位置：焊缝位置应便于施焊，尽可能对称分布焊缝； 合理地选择焊缝的尺寸和形式，焊缝设计为角焊缝、搭接焊缝（角焊缝焊接变形小于对接焊缝变形）； 3 1 `2、点固焊工艺对焊接变形的影响 2 e' }$ [8 l' x! w 1 L- l, {; [. ^% T 点固焊不仅能保证焊接间隙而且具有一定的抗变形能力。但是要考虑点固焊焊点的数量、尺寸以及焊点之间的距离。对于薄板的变形来说，点固焊工艺不合适就有可能在焊接之前就产生相当的残余焊接应力，对随后的焊接残余应力积累带来影响。点焊尺寸过小可能导致焊接过程中产生开裂使焊接间隙得不到保证，如果过大可能导致焊道背面未熔透而影响接头的美观连续性。点固焊的顺序、焊点距离的合理选择也相当重要。 J
# u: e# `$ x$ J& T% 3、装配应力及焊接程序对薄板焊接变形的影响 应尽量减少焊接装配过程中引起的应力，如果该应力超过产生变形的临界应力就可能产生变形。装配程序注意尽量避免强行组装，并核对坡口形式、坡口角度和组装位置， 对接接头焊接： 板厚≤2的无论单面焊还是双面焊都可以不开坡口， 对于板厚~双面焊可以不开坡口，但只能单面焊时，可以将坡口间隙放大到1~2mm或开坡口焊接； 板厚~双面焊时应在背面用小砂轮清根；只能单面焊时都应开坡口；
浅谈焊接技术及应用
浅谈焊接技术及应用 摘要:焊接专业作为制造业中的重要一环,在生产和生活中的作用十分重要。在焊接教学中应用一体化教学,为社会主义建设培养高素质高技能的焊接人才,是现阶段中等职业教育的首要任务。一体化教学强调一体化的教学场地、“双师型”教师及一体化教材的有机结合。发展一套适应中等职业教育的教学模式。 关键词:一体化教学场地双师型”教师一体化教材 1、“一体化”教学的目标 1.1 人才培养方式和教学课程的改革 改进人才培养方案,制定适合中等职业教育焊接专业“一体化”教学的人才培养方案。在原有的的国家教育部和劳动部颁发的只有中级焊工的教学大纲的基础上,制定适合培养高级工甚至技师的焊接专业的人才培养方案。 “打破原有课程体系将其分为素质课程、专业基础课程和专门工艺课程”,我们认为在这三者中应区别对待,在“专门课程”内容的制定上要体现区域经济的生产特征,结合生产产品制定相关内容和重点,有利于生产性实习或企业的定岗实习的顺利过渡而实现学与用的成功对接。制定和完善人才培养方案和培养模式,培养能满足社会需求的技能型人才。 1.2 一体化教学场地的建设 从根本上建立起黑板+粉笔教学和电化多媒体教学相结合的理论教学模式,是学生从直观上理解和接受理论知识。 校内实训基地受场地、设备等生产要素的限制,与生产车间客观上差距存在,在大型工装的应用,成型加工工件的变形与矫正等方面尤为突出。在这方面通过校企合作,将部分一体化的教学设置在与学校项邻的企业车间。 深化校企合作办学模式和工学结合人才培养模式改革。按照专业与产业对接、企业与岗位对接,专业课程内容与职业标准对接,教学过程与生产过程对接的原则,以校企合作为平台,以系统化专业建设为载体,突出教学过程的实践性、开放性和职业性,引导专业设置、课程体系、教学内容和教学方法的改革,实现“教、学、做”一体化的人才培养模式。 1.3 关于“双师型”师资队伍建设 “双师型、专业化”是职业教师发展的必经之路,在这方面注重中、青年教师在实践环节动手能力的提高,创造条件使他们带着具体的问题、任务去企业学习实践。使中青年教师在学历和理论知识占优的情况下,大幅度提高自身的实操能力。着力加强师资队伍建设,采取“引进来、送出去”、学历进修和非学历学习相结合等方式,努力培养一支优秀的专业师资队伍,加强建设培养学生创新精神与实践能力的实训平台。 2、“一体化”教学的主要过程 2.1 开发制定一体化课程教学标准 2.1.1 重构课程标准 打破原有学科体系,将课程体系分为基本素质课程、专业基础课程、专门工艺课程。 2.1.2 开展项目教学和案例教学 根据铆焊专业岗位层次的不同要求,实现课程改革与课程建设上的重大突破,完善高级铆焊专业课程体系建设,制定高中起点3年制、初中起点5年制高级铆
二保焊焊接工艺的设计说明
二保焊焊接工艺及技术 一、二氧化碳气体保护焊简介 二保焊是焊接方法中的一种，是以二氧化碳气为保护气体，进行焊接的方法。在应用方面操作简单，适合自动焊和全方位焊接。在焊接时不能有风，适合室作业由于它成本低，二氧化碳气体易生产，广泛应用于各大小企业二氧化碳气体保护电弧焊（简称CO2焊）的保护气体是二氧化碳有时采用CO2＋O2的混合气体。由于二氧化碳气体的0热物理性能的特殊影响，使用常规焊接电源时，焊丝端头熔化金属不可能形成平衡的轴向自由过渡，通常需要采用短路和熔滴缩颈爆断。因此，与MIG焊自由过渡相比，飞溅较多。但如采用优质焊机，参数选择合适，可以得到很稳定的焊接过程，使飞溅降低到最小的程度。由于所用保护气体价格低廉，采用短路过渡时焊缝成形良好。因此这种焊接方法目前已成为黑色金属材料最重要焊接方法之一。 1、短路过渡焊接 CO2电弧焊中短路过渡应用最广泛，主要用于薄板及全位置焊接，规参数为电弧电压焊接电流、焊接速度、焊接回路电感、气体流量及焊丝伸出长度等。 （1）电弧电压和焊接电流，对于一定的焊丝直径及焊接电流（即送丝速度），必须匹配合适的电弧电压，才能获得稳定的短路过渡过程，此时的飞溅最少。 （2）不同直径焊丝的短路过渡时参数如表：
（3）焊接回路电感，电感主要作用： a、调节短路电流增长速度di/dt, di/dt过小发生大颗粒飞溅至焊丝大段爆断而使电弧熄灭，di/dt 过大则产生大量小颗粒金属飞溅。 b、调节电弧燃烧时间控制母材熔深。 2、细颗粒过渡 在CO2气体中，对于一定的直径焊丝，当电流增大到一定数值后同时配以较高的电弧压，焊丝的熔化金属即以小颗粒自由飞落进入熔池，这种过渡形式为细颗粒过渡。 （1）细颗粒过渡时电弧穿透力强母材熔深大，适用于中厚板焊接结构。细颗粒过渡焊接时也采用直流反接法。 （2）达到细颗粒过渡的电流和电压围： 3、减少金属飞溅措施： （1）正确选择工艺参数，焊接电弧电压：在电弧中对于每种直径焊
高温合金材料介绍
MONEL 400 /UNS N04400 The alloy has excellent corrosion resistance in hydrofluoric acid and fluorine gas, and is suitable for pipe fittings and valves etc for chemical industry, petroleum, atomic energy, marine development. 在氢氟酸和氟气中具有优异的耐蚀性，适用于化工、石油、原子能、海洋开发中用的管件、阀件等。 NICKEL 200 ( UNS N02200 / DIN. W.Nr. 2.4060 ) The alloy is from pure commercial (99.6%) nickel, has good mechanical properties and excellent corrosion resistance, high thermal conductivity, low gas content and low vapor pressure. Mainly used in food processing equipment, salt refining equipment, mining and ocean mining. High temperature above 300 DEG C for manufacturing industrial sodium hydroxide required equipment. 是纯商业性（99.6%）造成的镍，具有优良的力学性能和优良的耐腐蚀性，较高的热和电导率，低气体含量和低蒸汽压力。主要应用于食物加工处理设备、食盐提炼设备、采矿和海洋开采。在300℃以上的高温条件下制造工业氢氧化钠所需的设备。 NICKEL 201 ( UNS N02201 / DIN. W.Nr. 2.4060 ) The alloy is a commercially pure nickel with very low carbon content and has been approved for use in a high temperature environment of up to 1230 degrees Celsius. 是含碳量极低的纯商业性镍，已被批准用于服务高达1230℃的高温环境中。 INCONEL 600 ( GB NS312 / UNS N06600 / DIN W.Nr.2.4816 / DIN NiCrl 5Fe / BS NA14 / AFNOR NC23FeA ) The alloy has high corrosion resistance against various corrosive media, also has good anti creep rupture strength. Recommended for the above 700 C working environment, mainly used for corrosive alkali metal production and application, especially the use of sulfide in the environment. 对于各种腐蚀介质都具有耐蚀性，还具有很好的抗蠕变断裂强度。推荐用于700℃以上的工
焊接技术的应用与前景
哈尔滨工业大学 金属工艺学课程论文 题目：焊接技术的应用与前景 院系：能源科学与工程学院 专业：核反应堆工程系 班级：1102301 学号：1110200724 姓名：刘平成
焊接技术的工艺应用与前景 作者：刘平成 (哈尔滨工业大学能源科学与工程学院核反应堆工程专业，哈尔滨150001) 摘要：制造业是现代国民经济和综合国力的重要支柱，金属工艺学是一门研究有关制造金属机件的工艺方法的综合性技术学科。本文主要介绍了焊接技术在金属工艺学中的应用，工艺特点，实践，背景与应用前景。 关键词：金属工艺学、学科交叉、工艺流程，焊接技术 Technology application and prospect of welding technology (Energy Science and Engineering, Nuclear Reactor Engineering of Harbin Institute of Technology, Harbin 150001) Abstract：The manufacturing industry is an important pillar of the modern national economy and overall national strength, Metal Technology is a comprehensive research process method for manufacturing metal parts technical disciplines. This paper describes the welding metal technology, process characteristics, practice, background and application prospects. 1 焊接技术的主要研究内容 焊接焊接是被焊工件的材质（同种或异种），通过加热或加压或两者并用，并且用或不用填充材料，使工件的材质达到原子间的结合而形成永久性连接的工艺过程。 1.1 焊接分类 在近代的金属加工中，焊接比铸造、锻压工艺发展较晚，但发展速度很快。焊接结构的重量约占钢材产量的45%，铝和铝合金焊接结构的比重也不断增加。焊接技术主要应用在金属母材上，常用的有电弧焊，氩弧焊，CO2保护焊，氧气-乙炔焊，激光焊接，电渣压力焊等多种，塑料等非金属材料亦可进行焊接。金属焊接方法有40种以上，主要分为熔焊、压焊和钎焊三大类。 金属的焊接，按其工艺过程的特点分有熔焊,压焊和钎焊三大类. 熔焊是在焊接过程中将工件接口加热至熔化状态，不加压力完成焊接的方法。熔焊时，热源将待焊两工件接口处迅速加热熔化，形成熔池。熔池随热源向前移动，冷却后形成连续焊缝
焊接作业指导书及焊接工艺
1．目的：明确工作职责，确保加工的合理性、正确性及可操作性。规范安全操作，防患于未然，杜绝安全隐患以达到安全生产并保证加工质量。 2．范围： 2.1.适用于钢结构的焊接作业。 2.2.不适用有特殊焊接要求的产品及压力容器等。 3．职责：指导焊接操作者实施焊接作业等工作。 4. 工作流程 4.1作业流程图
4.2.基本作业: 4.2.1.查看当班作业计划：按作业计划顺序及进度要求进行作业，以满足生产进度 的需要。 4.2.2.阅读图纸及工艺：施焊前焊工应仔细阅读图纸、技术要求及焊接工艺文件， 明白焊接符号的涵义。确定焊接基准和焊接步骤；自下料的要计算下料尺寸及用料规格，参照工艺要求下料。有半成品分件的要核对材料及尺寸，全部满足合焊图纸要求后再组焊。 4.2.3.校准：组焊前校准焊接所需工、量具及平台等。 4.2.4.自检、互检：所有焊接件先行点焊，点焊后都要进行自检、互检，大型、关 键件可由检验员配合检验，发现问题须及时调整。 4.2. 5.首件检验：在批量生产中，必须进行首件检查，合格后方能继续加工。 4.2.6.报检：工件焊接完成后及时报检，操作者需在图纸加工工艺卡片栏及施工作 业计划上签字。（外加工件附送货单及自检报告送检）。 5.工艺守则： 5.1.焊前准备 5.1.1.施焊前焊缝区（坡口面、I型接头立面及焊缝两侧）母材表面20～30mm宽范 围内的氧化物、油、垢锈等彻底清理干净，呈现均匀的金属光泽。
5.1.2.检查被焊件焊缝（坡口形式）的组对质量是否符合图纸要求，对保证焊接质 量进行评估，如有疑义应向有关部门联系，以便采取相应工艺措施。 5.1.3. 按被焊件相应的焊接工艺要求领取焊接材料，并确认焊接牌号无误。 5.1.4. 检查焊接设备是否运转正常，各仪表指数是否准确可靠，然后遵照本工艺提 供的工艺规范参数预调焊接电流、电压及保护气体流量。 5.1.5.合焊前应先行组对点焊，点焊的焊材应与正式施焊焊材相同，点焊长度一般 应为10-15mm（可视情况而定），点焊厚度应是焊脚高度的1/2（至少低于焊脚高度）。 5.1. 6.对于有焊前预热要求的焊件，根据工艺文件要求规范参数预热，温度必须经 热电偶测温仪测定，预热范围宽度应符合工艺文件的规定。 5.2.焊接过程 5.2.1.施焊过程应密切注视电弧的燃烧状况及母材金属与熔敷金属的熔合情况，发 现异常应及时调整或停止焊接，采取相应的改进措施。 5.2.2.多层焊时层间清渣要彻底，并自检焊缝表面发现缺陷及时修复，如焊接工艺 文件对层间温度有要求，必须保证层间温度符合工艺要求再焊下一层。 5.3.减少焊接应力变形的措施 5.3.1.刚性固定法：通常用于角变形较大的构件，施焊前加装若干块固定筋板其厚 度一般不小于8mm，对于较厚的焊件固定筋板的厚度应随之增大。
钛及钛合金论文
钛及钛合金 摘要：先进材料钛及钛合金的应用与前沿技术的发展一直是当前材料领域的热点研究课题之一。钛、钛合金及钛化合物的优良性能促使人类迫切需要它们。然而，生产成本之高，使应用受到限制。我们相信在不久的将来，随着钛的冶炼技术不断改进和提高，钛、钛合金及钛的化合物的应用将会得到更大的发展。本文介绍了钛合金的发展现状、特性、铸造工艺性能及其热处理，阐述了钛合金的生产技术及其应用，分析其优势与局限性，并展望发展趋势。 关键字：金属钛，钛合金; 发展状况;分布，性质; 铸造加工性能; 热处理;生产技术，应用; 研究前景 钛和钛合金的发展过程：钛是英国化学家格雷戈尔（Gregor R W ，1762—1817。）在1791年研究钛铁矿和金红石时发现的。四年后，1795年，德国化学家克拉普罗特(Klaproth M H ，1743—1817。）在分析匈牙利产的红色金红石时也发现了这种元素。他主张采取为铀（1789年由克拉普罗特发现的）命名的方法，引用希腊神话中泰坦神族“Titanic”的名字给这种新元素起名叫“Titanium”。中文按其译音定名为钛。 格雷戈尔和克拉普罗特当时所发现的钛是粉末状的二氧化钛，而不是金属钛。因为钛的氧化物极其稳定，而且金属钛能与氧、氮、氢、碳等直接激烈地化合，所以单质钛很难制取。直到1910年才被美国化学家亨特(Hunter M A）第一次制得纯度达99.9%的金属钛。 由于钛在液化状态时化学活性非常高, 钛与气体和所有制模成形用的难熔材料都有很高的活性, 因此, 钛合金铸造成形工业化的生产晚于变形钛合金和变形工艺。自海绵钛工业化以来, 钛在工业上的广泛应用推动了钛工业的迅速发展, 钛的生产能力正在逐年提升, 并将陆续超过铅、锌、铜成为名副其实的第三金属。目前, 由于国际紧张局势的缓和和军备缩减, 使军用飞机的钛需求量减少, 但民用客机今后可望继续增长。要使钛业得以生存, 普遍认为还是要扩大飞机以外的一般用途。近十几年来, 随着钛工业的发展,钛及钛合金已由军用逐渐转向民用, 由航空工业逐渐转向一般工业。 金属钛的地理分布：世界钛矿资源总体状况：截至1995年底，世界金红石（包括锐钛矿）储量和储量基
焊接工艺基本知识
焊接工艺基本知识 1什么是焊接接头？它有哪几种类型？ 用焊接方法连接的接头称为焊接接头（简称为接头）。它由焊缝、熔合区、热影响区及其邻近的母材组成。在焊接结构中焊接接头起两方面的作用，第一是连接作用，即把两焊件连接成一个整体；第二是传力作用，即传递焊件所承受的载荷。 根据GB/T3375—94《焊接名词术语》中的规定，焊接接头可分为10种类型，即对接接头、T形接头、十字接头、搭接接头、角接接头、端接接头、套管接头、斜对接接头、卷边接头和锁底接头，如图1。其中以对接接头和T形接头应用最为普遍。
2什么是坡口？常用坡口有哪些形式？ 根据设计或工艺需要，将焊件的待焊部位加工成一定几何形状的沟槽称为坡口。开坡口的目的是为了得到在焊件厚度上全部焊透的焊缝。 坡口的形式由 GB985—88《气焊、手工电弧焊及气体保护焊焊缝坡口的基本形式与尺寸》、GB986—88《埋弧焊焊缝坡口的基本形式及尺寸》标准制定的：常用的坡口形式有I形坡口、Y型坡口、带钝边U形坡口、双Y形 坡口、带钝边单边V形坡口等，见图2。
⑴坡口面焊件上所开坡口的表面称为坡口面，见图3。
⑵坡口面角度和坡口角度焊件表面的垂直面与坡口面之间的夹角称为坡口面角度，两坡口面之间的夹 角称为坡口角度，见图4。
开单面坡口时，坡口角度等于坡口面角度；开双面对称坡口时，坡口角度等于两倍的坡口面角度。坡口角度（或坡口面角度）应保证焊条能自由伸入坡口内部，不和两侧坡口面相碰，但角度太大将会消耗太多的填充材料， 并降低劳动生产率。
⑶根部间隙焊前，在接头根部之间预留的空隙称为根部间隙。亦称装配间隙。根部间隙的作用在于焊接底层焊道时，能保证根部可以焊透。因此，根部间隙太小时，将在根部产生焊不透现象；但太大的根部间隙，又会使根部烧穿，形成焊瘤。 ⑷钝边焊件开坡口时，沿焊件厚度方向未开坡口的端面部分称为钝边。钝边的作用是防止根部烧穿，但钝边值太大，又会使根部焊不透。 ⑸根部半径 U形坡口底部的半径称为根部半径。根部半径的作用是增大坡口根部的横向空间，使焊条能够伸入根部，促使根部焊透。 4试比较Y形、带钝边U形、双Y形三种坡口各自的优缺点？ 当焊件厚度相同时，三种坡口的几何形状见图5。
钛及钛合金力学性能
钛及钛合金力学性能 ，物理性能，以及相关介绍等 一。以下是个人对外六角螺栓和内六角螺栓使用情况的一点小总结，请参考俺的个人观点： 1。内六角的螺栓,适用于结构空间小,或者要求上平面是平面的情况下。 结构空间小，活动扳手占空间大,所以不能用，只能使用内六角螺栓，方便装卸。 产品要求安装后上平面是平面的情况下，主要适用于精密仪器/设备，一些设备要求安装后平面度的，或者要求整体产品外观良好，或者要求产品安装后上平面必须平，以此来避免挡碍的情况下需要使用内六角螺栓。 2。其他情况下，均建议用外六角螺栓。 3。从成本上考虑，用外六角螺栓，从外观效果上考虑，用内六角螺栓。 4。我们单位一般情况下，将内六角螺栓翻译为内六角螺钉，呵呵，请大家参考，也就是说一般意义上的内六角螺栓=内六角螺钉。当然，德标DIN和ISO 的标准正规些。 现在市场上的该类紧固件都在努力向DIN和ISO标准上靠拢。 二。钛及钛合金 钛及钛合金是导弹上重要结构材料之一。钛的密度为.507g/cm3,介于铝、铁之间。钛的熔点为1668℃比铁的熔点还高，能在高温下工作，耐热性能远超过铝。钛在含氧环境中易形成一层薄而坚固的氧化物薄膜。这层膜和基体结合牢固致密，破坏后还能自愈合，从而起到保护作用。 a.型钛合金
这类合金不能通过热处理强化，一般在退火状态下应用。它的特点是具有良好的耐热性和组织稳定性，低温性能优于其它类型钛合金。缺点是对变形抗力大，常温下强度不够高。 这类合金的牌号有TA1，…，TA7，TA8，其中TA1～TA3为工业纯钛； TA4，TA5，TA6属Ti-Al二元合金；TA4用作焊丝；TA5、TA6可用于一般结构件或耐蚀结构件；TA7是常用的典型型合金。 b.型钛合金 这类合金可通过淬火和时效得到强化，其优点是固溶处理状态下塑性很好，易加工成形，在时效状态下强度高。缺点是弹性模量低，耐热性差，焊接性能差，低温塑性不如型合金。 常用牌号为TB2，它可用于整体式固体火箭—冲压发动机的燃气发生器。 c.（+）型钛合金 这类合金的中国产品的牌号有TC1，…，TC4，…，TC10等品种，其中TC1和TC2为低强钛合金，TC3、TC4为中强钛合金，TC10属高强钛合金，TC6，TC9和TC11则属高强耐热钛合金。这类合金兼备钛合金和钛合金的优点。导弹上使用最多的是TC4（Ti-6Al-4V）钛合金，导弹上广泛的采用TC4钛合金制作高压气瓶，受力较大的杆式焊接支架，舵轴以及在较高热环境下工作的结构件，也可用作固体发动机壳体，压气机盘，叶片等。 (3)结构复合材料 复合材料是由两种或两种以上的性状不同的材料经选择、设计、成型而得到的一种宏观多相新材料。其组分可包括金属、非金属等各种材料，按作用又可分为基体材料和增强材料两部分。 三。钛及钛合金力学性能 牌号室温力学性能，不小于高温力学性能，不小于 抗拉强度σbMPa屈服强度σ0.2
焊接工艺及方法
焊接工艺及方法点焊方法和工艺。 1、焊点形成过程： （1）预压： （2）通电焊接： （3）锻压阶段：
二、点焊工艺参数选择 通常是根据工件的材料和厚度，参考该种材料的焊接条件表选取，首先确定电极的端面形状和尺寸。其次初步选定电极压力和焊接时间，然后调节焊接电流，以不同的电流焊接试样，经检查熔核直径符合要求后，再在适当的范围内调节电极压力，焊接时间和电流，进行试样的焊接和检验，直到焊点质量完全符合技术条件所规定的要求为止。最常用的检验试样的方法是撕开法，优质焊点的标志是：在撕开试样的一片上有圆孔，另一片上有圆凸台。厚板或淬火材料有时不能撕出圆孔和凸台，但可通过剪切的断口判断熔核的直径。必要时，还需进行低倍测量、拉抻试验和X光检验，以判定熔透率、抗剪强度和有无缩孔、裂纹等。 以试样选择工艺参数时，要充分考虑试样和工件在分流、铁磁性物质影响，以及装配间隙方面的差异，并适当加以调整。 三、不等厚度和不同材料的点焊
当进行不等厚度或不同材料点焊时，熔核将不对称于其交界面，而是向厚板或导电、导热性差的一边偏移，偏移的结果将使薄件或导电、导热性好的工件焊透率减小，焊点强度降低。熔核偏移是由两工件产热和散热条件不相同引起的。厚度不等时，厚件一边电阻大、交界面离电极远，故产热多而散热少，致使熔核偏向厚件；材料不同时，导电、导热性差的材料产热易而散热难，故熔核也偏向这种材料调整熔核偏移的原则是：增加薄板或导电、导热性好的工件的产热而减少其散热。常用的方法有： （1）采用强条件使工件间接触电阻产热的影响增大，电极散热的影响降低。电容储能焊机采用大电流和短的通电时间就能焊接厚度比很大的工件就是明显的例证。 （2）采用不同接触表面直径的电极在薄件或导电、导热性好的工件一侧采用较小直径，以增加这一侧的电流密度、并减少电极散热的影响。 （3）采用不同的电极材料薄板或导电、导热性好的工件一侧采用导热性较差的铜合金，以减少这一侧的热损失。 （4）采用工艺垫片在薄件或导电、导热性好的工件一侧垫一块由导热性较差的金属制成的垫片（厚度为0.2-0.3mm），以减少这一侧的散热。
GH3030高温合金介绍
GH3030高温合金 GH30固溶强化型高温合金 80Ni-20Cr板 gh3030棒国军标 GH3030(GH30) 固溶强化型变形高温合金 GH3030特性及应用领域概述： 该合金是早期发展的80Ni-20Cr固溶强化型高温合金，化学成分简单，在800℃以下具有满意的热强性和高的塑性，并具有良好的抗氧化、热疲劳、冷冲压和焊接工艺性能。合金经固溶处理后为单相奥氏体，使用过程中组织稳定。主要用于800℃以下工作的涡轮发动机燃烧室部件和在1100℃以下要求抗氧化但承受载荷很小的其他高温部件。 GH3030相近牌号： GH30，Зи435，XH78T(俄罗斯) GH3030 化学成分：（GB/T14992-2005） GH3030物理性能：
GH3030力学性能：(在20℃检测机械性能的最小值) GH3030生产执行标准： GH3030 金相组织结构： 该合金在1000℃固溶处理后为单相奥氏体组织，间有少量TiC和Ti(CN)。GH3030工艺性能与要求： 1、该合金具有良好的可锻性能，锻造加热温度1180℃，终锻900℃。 2、该合金的晶粒度平均尺寸与锻件的变形程度、终锻温度密切相关。 3、热处理后，零件表面氧化皮可用吹砂或酸洗方法清除。 GH3030主要规格： GH3030无缝管、GH3030钢板、GH3030圆钢、GH3030锻件、GH3030法兰、 GH3030圆环、GH3030焊管、GH3030钢带、GH3030直条、GH3030丝材及配套焊材、GH3030圆饼、GH3030扁钢、GH3030六角棒、GH3030大小头、GH3030弯头、GH3030三通、GH3030加工件、GH3030螺栓螺母、GH3030紧固件。 篇幅有限，如需更多更详细介绍，欢迎咨询了解。
二氧化碳气体保护焊焊接工艺及应用
二氧化碳气体保护焊焊接工艺及应用
二氧化碳气体保护焊焊接 工艺及应用 广西送变电建设公司铁塔厂
2、T形接头角焊缝试验 ①材料Q235-A，300m m×125m m×10m m，2块，不开坡口，单道焊。 ②焊接方法及焊接材料焊条电弧焊,E4303，Φ3.2mm；CO2气保焊、富氩气保焊，焊丝ER50-6，Φ1.2mm；富氩气：80%Ar+20% CO2。 ③检验内容外观检查，切取5个截面进行金相宏观检查。要求断面无裂纹，无未焊透，无未熔合缺陷。 3、T形接头角焊缝成形、飞溅试验试验条件同2.2，通过对比试验对CO2气保焊、富氩气保焊进行外观成形及飞溅大小进行评定。 焊接试验结果分析 ①从对接接头焊缝力学性能试验可知，3种焊接方法的焊接接头外观检查符合要求，RT检验均高于E级合格，焊接接头的抗拉强度以富氩气保焊最高，CO2气保焊次之，焊条电弧焊最低，这是因为富氩气保焊氧化性较少，合金元素烧损较少所致，但它们均高于母材规定的最小值。按规定的弯曲角，每个试件面弯、背弯各2个，弯曲试验合格。这说明3种焊接方法及焊接工艺的焊接接头力学性能试验合格。但富氩气保焊、CO2气保焊坡口角度较少，钝边较大，比焊条电弧生产率高，节省材料，成本低，焊接变形少。这是因为气体保护焊焊丝较细，电流密度大，熔深大，电弧穿透力强，易焊透所致。 ②从T形接头角焊缝试验可知，3种焊接方法的熔深大小分别为：富氩气保焊熔深略大于CO2气保焊，大于焊条电弧焊，每个试件的5个断面根部均未出现裂纹、未熔合、未焊透缺陷，宏观金相检验合格。
③从T形接头角焊缝飞溅、成形试验可知，富氩气保焊的飞溅较小，最大飞溅颗粒直径大小为Φ1.5mm～Φ2mm，CO2气保焊飞溅稍大，最大飞溅颗粒直径为Φ3mm～Φ4mm；富氩气保焊焊缝表面较CO2焊波纹细密，成形美观。 综上所述：三种焊接方法及焊接工艺均能满足力学性能要求及宏观金相要求。但CO2气保焊、富氩气保焊，焊丝较细，电流密度大，热量集中，电弧穿透力强，熔深大，可以减少坡口角度，增加钝边厚度，节省材料，提高劳动生率，降低焊接应力与变形。富氩气保焊较CO2气保焊成形美观，飞溅小，但成本较高。所以除了对极少数外观要求较高的焊缝采用富氩气保焊外，其余均采用CO2气保焊。 三、焊接工艺 1、焊前准备 ①清除待焊部位及两侧10～20mm范围内的油污、锈迹等污物，并在焊件表面涂上一层飞溅防粘济，在喷嘴上涂一层喷嘴防堵济。 ②将CO2气瓶倒置1～2h，使水分下沉，每隔0.5h放水1次，放2～3次。 ③根据焊接工艺试验编制焊接工艺。焊丝ER5026，Φ1.0mm，Φ 1.2mm，焊机KRII350。 ④采用左焊法。 四、焊接操作工艺 1、对接焊缝操作工艺 ①由于CO2气保焊熔深大，在板厚小于12mm时均可用工形坡口（不
高温合金材料的应用与发展
高温合金材料的应用与发展分析 李桃山王保山 南昌航空大学飞行器工程学院100631班：10号 南昌航空大学飞行器工程学院100631班：20号 摘要： 本文主要介绍高温合金材料的定义及加工特点，通过了解合金的使用范围及选择标准，使更好的发展运用在各个领域。随着工业技术的发展。要求使用具有耐更高温度下的疲劳、蠕变、热稳定性以及抗氧化性能的高温材料，以适应先进设备（主要是航空运用）的设计要求，因此近半个多世纪以来人们从未停止过对的各种高温合金材料研发。从我国高温材料的发展历程与现状分析认为，我们应该发扬民主, 军民结合, 发扬全国一盘棋的精神, 形成一个和谐的集体，使我国高温合金体系建立在一个更坚实的基础上。 关键字：高温合金材料合金分类应用合金发展前景选择标准 前言： 高温钛合金以其优良的热强性和高比强度，在航空发动机上获得了广泛的应用。类似的高温合金材料在未来很长的一段时间应该是王牌型材料，在科技日新月异的今天，对高温合金材料的研究与来发具有很高的实际意义与战略意义。未来的航空航天飞行器及其推力系统，要求发展比现有的Ti64和Ti6242合金的强度、工作温度和弹性模量更高，密度更小，价格更低的高温合金材料，因此，高温合金材料的是航空材料的发展主流。 一、高温合金材料的定义及加工特点 高温合金定义：高温合金是指以铁、镍、钴为基，能在600℃以上的高温及一定应力作用下长期工作的一类金属材料。并具有较高的高温强度，良好的抗氧化和抗腐蚀性能，良好的疲劳性能、断裂韧性等综合性能。高温合金为单一奥氏体组织，在各种温度下具有良好的组织稳定性和使用可靠性。 高温合金加工特点 对于镍合金、钛合金以及钴合金等高温合金来说，耐高温的特性直接提高了
部分高温合金牌号及成分
部分高温合金牌号及成分
部分特种合金牌号及成分Monel 400 相近牌号 UNS Trademark W.Nr N04400Monel400 2.4360 Monel 400 的化学成分: Monel 400 的物理性能: 在常温下合金的机械性能的最小值: Monel 400
Monel 400特性： Monel400是一种用量最大、用途最广、综合性能极佳的耐蚀合金。此合金在氢氟酸和氟气介质中具有优异的耐蚀性，对热浓碱液也有优良的耐蚀性。同时还耐中性溶液、水、海水、大气、有机化合物等的腐蚀。该合金的一个重要特征是一般不产生应力腐蚀裂纹，切削性能良好。 Monel 400 的金相结构: Monel400合金的组织为高强度的单相固溶体。 Monel 400 的耐腐蚀性: Monel400合金在氟气、盐酸、硫酸、氢氟酸以及它们的派生物中有极优秀的耐蚀性。同时在海水中比铜基合金更具耐蚀性。酸介质：Monel400在浓度小于85%的硫酸中都是耐蚀的。Monel400是可耐氢氟酸中为数极少的重要材料之一。水腐蚀：Monel400合金在多数水腐蚀情况下，不仅耐蚀性极佳，而且孔蚀、应力腐蚀等也很少发现，腐蚀速度小于0.025mm/a。高温腐蚀：Monel400在空气中连续工作的最高温度一般在600℃左右，在高温蒸汽中，腐蚀速度小于0.026mm/a。氨：由于Monel400合金镍含量高，故可耐585℃以下无水氨和氨化条件下的腐蚀。
Monel 400 应用领域： Monel400合金是一种多用途的材料，在许多工业领域都能应用： 1.动力工厂中的无缝输水管、蒸汽管 2.海水交换器和蒸发器 3.硫酸和盐酸环境 4.原油蒸馏 5.在海水使用设备的泵轴和螺旋桨 6.核工业用于制造铀提炼和同位素分离的设备 7.制造生产盐酸设备使用的泵和阀 Monel K500 相近牌号 UNS Trademark N05500MonelK500 Monel K500 的化学成分:
二氧化碳气体保护焊焊接的实用实用工艺及的应用
二氧化碳气体保护焊焊接 工艺及应用 广西送变电建设公司铁塔厂
二氧化碳气体保护焊焊接工艺及应用 XX送变电铁塔厂 XX 【摘要】通过对CO2气保焊、富氩气保焊、焊条电弧焊3种焊接方法进行焊接接头试验和对比分析。以及在工程机械中的应用，证明了CO2气保焊具有成本低，效率高，焊接质量好等优点。 介绍了CO2气保焊焊接操作技术需注意的一些问题，对CO2气保焊焊接工艺设计及其应用具有一定的指导作用。 【引言】二氧化碳气体保护焊在焊接过程稳定，飞溅嘴角，焊缝外形美观，无气孔、裂缝及咬边等缺陷。对双面焊或单面焊双面成型的焊缝能保证焊透，具有最高生产率。 例如：某制造厂为一大型工程机械公司生产一百多米高的塔式起重机等工程机械部件，这些部件均为焊接件，焊接工作量大，焊接质量要求较高，技术难度较大。原采用焊条电弧焊，焊接变形大且难以控制，生产率低。通过对CO2气保焊、富氩气保焊及焊条电弧焊进行对比工艺试验及评定，决定除对个别有外观要求的焊缝采用富氩气体保护焊外，其余均采用CO2气保焊。生产实践证明，这样即保证了焊接质量，又提高了劳动生产率，降低了成本，取对了较好的经济效益。
一、焊接接头情况及焊缝技术要求 1、焊接接头形式有对接接头、角接接头、T形接头及搭接接头，其中绝大部分是T形接头。 2、焊缝形式有对接焊缝及角焊缝，大部分为角焊缝，由于板厚不同，焊脚分别为6mm，8mm，10mm，12mm，15mm不等。 3、母材主要为碳素结构钢板Q2352A，规格有6mm，8mm，10mm，12mm，20mm，25mm等几种。 4、焊缝外观要求，焊缝及热影响区表面不得有裂纹、气孔、夹渣、未熔合等缺陷。焊缝形状尺寸符合图样要求，焊缝与母材平滑过度。部分焊缝要求超声波探伤合格。 二、焊接试验 参照JB4708-2000《压力容器焊接工艺评定》，进行CO2气保焊、富氩气保焊、焊条电弧焊对接接头力学性能试验，T形接头角焊缝试验及CO2气保焊、富氩气保焊飞溅成形工艺性能，进行对比分析。 1、对接接头力学性能试验 ①试验材料 Q235-A，300mm×125mm×10mm，2块；焊条电弧焊开60V形坡口，CO2气保焊、富氩气保焊开45V形坡口，单面焊双面成形。 ②焊接方法及焊接材料焊条电弧焊,E4303，Φ3.2mm，Φ4mm；CO2气保焊、富氩气保焊焊丝ER50-6，5Φ1.2；富氩气：80%Ar+20%CO2。 ③检验容外观检查，RT检查，力学性能试验（拉力试验、弯曲试验）。 2、T形接头角焊缝试验
焊接工艺评定说明教学文稿
SWT50 履带吊工艺评定方案简述为了保证各关键构件强度，对构件中的相关重要连接焊缝有所保证。在焊前、焊中、焊后都需进行严格的监控。对关键焊缝的焊前制定出焊接工艺，并对相关焊接工艺进行评定工作。 据： ISO15611：2003 金属材料焊接工艺规程及评定-基于焊接经验的评定 ISO15612：2004 金属材料焊接工艺规程及评定-基于标准焊接规程的评定 ISO15614-1：2004 金属材料焊接工艺规程及评定-焊接工艺评定试验-第一部分：钢的弧焊和气焊、镍及镍合金的弧焊ISO4136：2001 金属材料焊缝的破坏性试验-横向拉伸试验 ISO5173：2000 金属材料焊缝的破坏性试验-弯曲试验 ISO9015-1：2001 金属材料焊缝的破坏性试验-硬度试验-第1 部分：电弧焊接头硬度试验 ISO9015-2：2003 金属材料焊缝的破坏性试验-硬度试验-第2 部分：焊接接头显微硬度试验 ISO9018：2003 金属材料焊缝的破坏性试验-十字接头和搭接接头的拉伸试验 ISO17635：2003 焊缝的无损检测-金属材料熔化焊焊缝的一般原则 ISO17636：2003 焊缝的无损检测-熔化焊接头的射线检测 ISO17637：2003 焊缝的无损检测-熔化焊接头的外观检验 ISO17639：2003 金属材料焊缝的破坏性试验-焊缝宏观和微观检验 ISOTR16060 ：2003 金属材料的破坏性试验-宏观和微观检验用腐蚀剂
渗透检验： 磁粉检验: 超声波检验: 硬度试验： 类别/载荷： 断口试验： 母材： 热影响区： 焊缝： 其它试验： 备注： 试验依据： 检验员师或试验机构: 试验结果： 试验在场人员： 日期： 弯曲试验： 试验标准: 宏观金相: 微观金相: 射线检验:
激光焊接技术应用及其发展趋势(精)
激光焊接技术应用及其发展趋势 激光焊接是激光加工材料加工技术应用的重要方面之一。70年代主要用于焊接薄壁材料和低速焊接，焊接过程属于热传导型，即激光辐射加热工件表面，表面热量通过热传导向内部扩散，通过控制激光脉冲的宽度、能量、峰值功率和重复频率等参数，使工件熔化，形成特定的熔池。由于激光焊接作为一种高质量、高精度、低变形、高效率和高速度的焊接方法，随着高功率CO2和高功率的YAG 激光器以及光纤传输技术的完善、金属钼焊接聚束物镜等的研制成功，使其在机械制造、航空航天、汽车工业、粉末冶金、生物医学微电子行业等领域的应用越来越广。目前的研究主要集中于C02激光和YAG激光焊接各种金属材料时的理论，包括激光诱发的等离子体的分光、吸收、散射特性以及激光焊接智能化控制、复合焊接、激光焊接现象及小孔行为、焊接缺陷发生机理与防止方法等，并对镍基耐热合金、铝合金及镁合金的焊接性，焊接现象建模与数值模拟，钢铁材料、铜、铝合金与异种材料的连接，激光接头性能评价等方面做了一定的研究。 一、激光焊接的质量与特点 激光焊接原理：激光焊接是将高强度的激光束辐射至金属表面，通过激光与金属的相互作用，金属吸收激光转化为热能使金属熔化后冷却结晶形成焊接。图1显示在不同的辐射功率密度下熔化过程的演变阶段[2]，激光焊接的机理有两种： 1、热传导焊接 当激光照射在材料表面时，一部分激光被反射，一部分被材料吸收，将光能转化为热能而加热熔化，材料表面层的热以热传导的方式继续向材料深处传递，最后将两焊件熔接在一起。 2、激光深熔焊 当功率密度比较大的激光束照射到材料表面时，材料吸收光能转化为热能，材料被加热熔化至汽化，产生大量的金属蒸汽，在蒸汽退出表面时产生的反作用力下，使熔化的金属液体向四周排挤，形成凹坑，随着激光的继续照射，凹坑穿入更深，当激光停止照射后，凹坑周边的熔液回流，冷却凝固后将两焊件焊接在—起。 这两种焊接机理根据实际的材料性质和焊接需要来选择，通过调节激光的各焊接工艺参数得到不同的焊接机理。这两种方式最基本的区别在于：前者熔池表面保持封闭，而后者熔池则被激光束穿透成孔。传导焊对系统的扰动较小，因为激光束的辐射没有穿透被焊材料，所以，在传导焊过程中焊缝不易被气体侵入；而深熔焊时，小孔的不断关闭能导致气孔。传导焊和深熔焊方式也可以在同一焊接过程中相互转换，由传导方式向小孔方式的转变取决于施加于工件的峰值激光能量密度和激光脉冲持续时间。激光脉冲能量密度的时间依赖性能够使激光
焊接工艺评定、焊接工艺规程实用编制方法
焊接工艺评定、焊接工艺规程的实用编制方法 一、焊接工艺评定的有关概念 二、焊接工艺评定及使用管理程序 三、焊接工艺评定变素及其评定规则 四、如何阅读焊接工艺评定报告 五、如何编制焊接工艺规程 一、焊接工艺评定的有关概念 1、焊接工艺评定的定义和目的 2、消除焊接工艺评定认识上误区： 3、“焊接性能”与“焊接性” 4、“焊接性能试验”与“焊接工艺评定” 5、“焊缝”与“焊接接头” 6、“焊接工艺评定”与“焊工技能考试” 7、焊接工艺评定的基本条件 8、常用焊接工艺评定标准： JB4708－2000《钢制压力容器焊接工艺评定》 GB50236－98《现场设备、工业管道焊接工程施工及验收规范》第4章 劳部发1996[276]号《蒸汽锅炉安全监察规程》附录I JGJ81-2000《建筑钢结构焊接技术规程》第5章 GB128-90《立式圆筒形钢制焊接油罐施工及验收规范》附录一 ASME第IX卷《焊接与钎焊》 二、焊接工艺评定及使用管理程序 1、焊接工艺评定程序 （1）焊接工艺评定立项 （2）焊接工艺评定委托 （3）编制焊接工艺指导书（WPI）并批准 （4）评定试板的焊接 （5）评定试板的检验 焊接工艺评定失败，重新修改焊接工艺指导书，重复进行上述程序。
（6）编写焊接工艺评定报告（PQR）并批准 2、焊接工艺评定文件的使用与管理 （1）焊接工艺评定文件的受控登记。 （2）焊接工艺评定的有效版本及换版转换。 （3）每季度编制焊接工艺评定文件的有效版本目录。 （4）保证现场工程和产品的焊接工艺评定的覆盖率为100%。 （5）焊接工艺评定文件作为公司的一项焊接技术储备，属于公司重要技术机密文件，应妥善保管。 三、焊接工艺评定变素及其评定规则 1、焊接工艺评定的主要变素： 试件形式 母材类别 焊接方法 焊接工艺因素 焊后热处理种类及参数 母材厚度 焊缝熔敷金属厚度 四、如何阅读焊接工艺评定报告 1、如何认识焊接工艺评定报告的作用 （1）焊接工艺评定报告的合法性： （2）焊接工艺评定报告的有效性： （3）焊接工艺评定报告及焊接工艺规程的局限性： （4）焊接工艺评定报告是一种必须由企业焊接责任工程师和总工程师签字的重要质保文件，也是技术监督部门和用户代表审核施工企业质保能力的主要依据之一。 2、焊接工艺评定报告与焊接工艺规程的关系 3、阅读焊接工艺评定报告的方法 五、如何编制焊接工艺规程 1、焊接工艺规程的作用 2、焊接工艺规程的基本要求 3、焊接工艺规程的编写应遵循的原则