中硬重载齿轮焊接工艺及制造技术研究

对齿轮用钢３０ＣｒＭｏ，４０ＣｒＮｉ２Ｍｏ，４０ＣｒＭｎＭｏ钢进行了焊接性试验，结果表明：该钢冷裂倾向严重，过热区易淬硬，冲击韧性差，预热及焊后热处理，，选择药芯焊丝Ｅ７０Ｔ－５ＣＯ２焊及ＭＡＧ焊，接头性能可满足技术要求。还介绍了齿轮的制造工艺装焊胎卡具。     

9Cr1MoV钢焊接性试验及其应用

为研究９Ｃｒ１ＭｏＶ钢的焊接性，进行了斜Ｙ形超口焊接裂纹试验和插销及可调拘束裂纹试验。指出，９Ｃｒ１ＭｏＶ钢存在一定的冷裂和热裂倾向。采有相应的工艺措施和合适的焊接材料，避免了焊接接头冷热裂纹。还介绍了３００ＭＷ锅炉９Ｃｒ１ＭｏＶ钢管Ｍ１Ｇ焊及手工Ｔ１Ｇ焊的焊接工艺评定结果和焊接工艺规程。     

文摘

９９０５０２０　锅炉用１２Ｃｒ－０．４Ｍｏ－２Ｗ钢管和２．２５Ｃｒ－１．６Ｗ钢管长时期使用后的组织［刊,日］宫田佳织…∥材料とプロセス．１９９８,１１（６）住友金属工业公司对１２Ｃｕ－０．４Ｍｏ－１Ｃｒ－Ｖ－Ｎｂ钢（Ｔ１２２）和２．２５Ｃｒ－１．６Ｗ－Ｖ－Ｎ钢（Ｔ２３）在使用了２．５年后取样,研究其组织变化状况与蠕变强度的关系。所取试样为冷拔无缝钢管,使用前经过了正火＋回火处理。使用时的锅炉蒸气温度为５７１℃（过热器出口）和５４３℃（再热器出口）,最高压力为１９．２ＭＰａ（过热器）和４．２ＭＰａ…     

20G和2.25Cr—1Mo钢氢蚀后的疲劳性能

对２０Ｇ和２．２５Ｃｒ－１Ｍｏ钢经不同程度氢蚀后的常规力学性能与疲劳裂纹扩展行为进行了对比研究。并对氢蚀组织变化与裂纹扩展路径进行了显微观察。结果表明，氢蚀使２０Ｇ钢的疲劳裂纹扩展速率明显增大；扩展门槛值在氢蚀起始阶段显著降低，随后又呈增加趋势。对２．２５Ｃｒ－１Ｍｏ钢，由于元素Ｃｒ、Ｍｏ作用，其氢蚀程度远低于２０Ｇ钢，从而未造成疲劳裂纹扩展速率的明显改变。分析表明，氢蚀后疲劳裂纹扩展门槛值的上升     

Mn对热作模具钢4Cr3Mo2NiVNb热疲劳性能的影响

采用Ｕｅｄｅｈｏｌｍ法研究热作模具钢４Ｃｒ３Ｍｏ２ＮｉＶＮｂ和添加１．５％Ｍｎ后该钢的热疲劳性能。结果表明，添加１．５％Ｍｎ后，４Ｃｒ３Ｍｏ２ＮｉＶＮｂ钢的热疲劳抗力有所下降。试验结果同时表明，影响热作模具钢低周热疲劳的主要因素是钢的断裂韧性。     

Mn对热作模具钢4Cr3Mo2NiVNB热疲劳性能的影响

采用Ｕｏｄｅｈｏｌｍ法研究热作模具４Ｃｒ３Ｍｏ２ＮｉＶＮｂ和添加剂１．５％Ｍｎ后该钢的热疲劳性能。结果表明，添加１．５％Ｍｎ后，４Ｃｒ３Ｍｏ２ＮｉＶＮｂ钢的疲劳抗力有所下降，试验结果同时表明，影响热作模具钢低周热疲劳的主要因素是钢的断裂韧性。     

10CrMo910钢厚壁管接头取消焊后热处理的研究

采用深缺口插销法评定了１０ＣｒＭｏ９１０钢冷裂纹和再热裂纹敏感性；采用高温模拟试验对比了未经焊后热处理的１０ＣｒＭｏ９１０钢厚壁管接头的性能。试验结果表明：（１）３５ｍｍ厚的１０ＣｒＭｏ９１０钢接头焊前预热（１００￣２００）℃可防止冷裂纹；（２）１０ＣｒＭｏ９１０钢裂纹敏感性轻微，取消其焊后热处理，在高温运行过程中不会产生再热裂纹；（３）未经焊后热处理的１０ＣｒＭｏ９１０管接头具有更优良的力学性能     

20G和2．25Cr—1Mo钢氢蚀后的疲劳性能

对２０Ｇ和２．２５Ｃｒ－１Ｍｏ钢经不同程度氢蚀后的常规力学性能与疲劳裂纹扩展行为进行了对比研究。并对氢蚀组织变化与裂纹扩展路径进行了显微观察。结果表明，氢蚀使２０Ｇ钢的疲劳裂纹扩展速率明显增大；扩展门槛值在氢蚀起始阶段显著降低，随后又呈增加趋势，对２．２５Ｃｒ－１Ｍｏ钢，由于元素Ｃｒ，Ｍｏ的作用，其氢蚀程度远低于２０Ｇ钢，从而未造成疲劳裂纹扩展速率的明显改变，分析表明，氢蚀后疲劳裂纹扩展门槛值的上升可以归因于曲折开裂路径造成裂纹闭合效应的增加。     

4Cr3Mo2V钢高速热模锻模具的应用研究

试验研究了用于ＡＭＰ５０－ＸＬ高速热模锻机的４Ｃｒ３Ｍｏ２Ｖ钢热作模具。生产试验表明，新开发的４Ｃｒ３Ｍｏ２Ｖ负热锻模的使用寿命明显高于Ｈ１１钢热锻模，也略高于Ｘ３２ＣｒＭｏＣｏＶ３３３钢热锻模的使用寿命。     

冷模具钢渗扩氮复合强韧化研究

研究了渗扩氮等温淬火对Ｃｒ７Ｍｏ３Ｖ２Ｓｉ和Ｃｒ１２ＭｏＶ钢、渗扩氮冷待淬火对６０Ｓｉ２Ｍｎ钢的显微组织分布、显微硬度梯度曲线的影响。结果表明，Ｃｒ７Ｍｏ３Ｖ２Ｓｉ和Ｃｒ１２ＭｏＶ钢制冷模具经渗扩氮等温淬火复合强韧化及６０Ｓｉ２Ｍｎ钢冷模具经渗扩氮冷待淬火复合强韧化处理后的使用寿命显著提高。     

A517Q齿条钢的焊接性

通过斜Y坡口焊接裂纹试验、焊接热影响区最高硬度试验和焊接接头力学性能试验,系统地研究了A517Q齿条钢的焊接性. 结果表明,在拘束焊接时,A517Q齿条钢的焊接冷裂纹敏感性随钢板厚度由30 mm增大至60 mm而增大;提高预热温度有助于降低该钢的焊接冷裂倾向和热影响区的淬硬程度. 177.8 mm厚A517Q齿条钢板的焊接接头具有高强度和高韧性,能够满足使用性能要求;焊接热影响区的显微组织以低碳板条马氏体和板条贝氏体为主,该区硬度明显高出焊缝区和母材区,淬硬倾向较大,存在一定的冷裂风险.     

铁路车辆用TCS耐蚀钢的焊接性研究

通过冷裂敏感性试验、焊接热影响区最高硬度试验及可调拘束试验,对新型铁路车辆用TCS耐蚀钢的焊接性进行了深入系统分析.结果表明,TCS钢具有良好的抗冷裂敏感性和抗结晶热裂敏感性能.     

灰铸铁同质焊缝电弧冷焊接头冷裂纹研究进展

从焊缝石墨形态及焊缝组织对冷裂纹的影响、铸铁型焊缝冷裂纹产生机理及裂纹萌生与扩展的微观过程、热影响区冷裂纹研究、铸铁焊接接头冷裂纹试验方法等四个方面综述了国内外灰铸铁同质焊缝电弧冷焊焊接接头冷裂纹的研究进展,研究发现,石墨呈球状的可以大为改善焊缝的抗裂性;利用贝氏体马氏体二次相变应力松驰效应可以降低灰铸铁焊缝裂纹敏感性;裂纹容易在相邻石墨间的窄铁素体基体桥处萌生与扩展;扩散氢对灰铸铁接头热影响区冷裂纹影响小而马氏体相变影响大。在灰铸铁焊接冷裂纹试验方法方面,重点讨论了能定量评定焊缝抗裂性的铸铁焊缝拘束裂纹试验及平板刚性拘束裂纹（PRRC）试验。     

HAZ CRACKING AND HOT DUCTILITY OF Ni_3AI CONTAINING Zr ALLOY

1.~hoNi,AIalloyisanewpotentialhightemperaturestmcturalmaterialbecauseofitsexcellentstrengthandanti--corrosionpropertiesinhightemperatureservice.ButtherearebrittlephenomenainitspolygonalcrystalmaterialduringdifferenttemperaturerangebecauseofitsLI,typeintermetalliccompounds.ThusitsengineeringaPPlicationislicitted.ThisbrittlenesscanhereducedwithadditionofthialelementsB,Zr,Hf,CrandFeandsoon.AfewliteraturesareavailableaboutthefusionweldingofNi,kialloysandmat4fromOakfudgeNationalbooratory,U.S…     

低硅TRIP钢焊接性能试验研究

通过对0．11C-0．6Si-1．6Mn TRIP钢的V型和Y型焊接接头进行综合力学性能测试和冷裂缝试验,研究该钢种的焊接性能。结果表明新型TRIP钢焊接接头的综合力学性能和冲击韧性良好;虽然焊接热影响区硬化较明显,但由于焊接后无冷裂纹和低温裂纹产生,可焊性很好,不用预热焊接。由此已成功地应用于轿车制动踏板臂的制造。     

防护钢的焊接冷裂纹敏感性研究

通过冷裂纹敏感指数计算、焊缝接头硬度试验和斜Y型坡口试验,分析防护钢板的焊接冷裂纹敏感性。结果表明,防护钢板冷裂纹敏感指数Pcm=0.329%,不产生冷裂纹的预热温度为172℃。在常温和预热172℃条件下,热影响区的最高硬度分别为475 HV和310 HV;斜Y型坡口试验在室温条件下焊接时,焊缝表面裂纹率为0,平均断面裂纹率为10.5%,在172℃预热条件下焊接时,焊缝表面和断面裂纹率均为0。     

在役球罐再次组焊冷裂纹敏感性研究

服役十年之后的07MnCrMoVR球罐需进行分拆搬迁,然后重新组焊.通过斜Y坡口对接裂纹试验和HAZ最高硬度试验对球罐材料再次组焊的冷裂纹敏感性进行研究,建议施工现场焊前预热温度不低于75℃.     

Weldability and toughness evaluation of pressure vessel quality steel using the shielded metal arc welding (SMAW) process

The present study was carried out to assess the weldability properties of ASTM A 537 Cl. 1 pressure-vessel quality steel using the shielded metal arc welding (SMAW) process. Implant and elastic restraint cracking (ERC) tests were conducted under different welding conditions to determine the cold cracking susceptibility of the steel. The static fatigue limit values determined for the implant test indicate adequate resistance to cold cracking even with unbaked electrodes. The ERC test, however, established the necessity to rebake the electrodes before use. Lamellar tearing tests carried out using full-thickness plates under three welding conditions showed no incidence of lamellar tearing upon visual examination, ultrasonic inspection, and four-section macroexamination. Lamellar tearing tests were repeated using machined plates, such that the central segregated band located at the midthickness of the plate corresponded to the heat-affected zone (HAZ) of the weld. Only in one (no rebake, heat input: 14.2 kj cm^-1, weld restraint load: 42 kg mm^-2) of the eight samples tested was lamellar tearing observed. This was probably accentuated due to the combined effects of the presence of localized pockets of a hard phase (bainite) and a high hydrogen level (unbaked electrodes) in the weld joint. Optimal welding conditions were formulated based on the above tests. The weld joint was subjected to extensive tests and found to exhibit excellent strength (tensile strength: 56.8 kg mm^-2, or 557 MPa), and low temperature impact toughness (7.4 and 4.5 kg-m at-20 °C for weld metal, WM, and HAZ) properties. Crack tip opening displacement tests carried out for the WM and HAZ resulted in δ_m values 0.36 and 0.27 mm, respectively, which indicates adequate resistance to brittle fracture.     

Hot cracking of welds on heat treatable aluminium alloys

Abstract

The Spot Varestraint test was used to evaluate the hot cracking susceptibility of several aluminium alloys namely 6061-T6, 6061-T6 (H), 7075-T6, 7075-T6 (H). The effects of augment strain, the number of thermal cycles and cold working (rolling) on the cracking susceptibility were investigated, and the total crack length was used to evaluate the hot cracking susceptibility. The results indicate that the number of thermal cycles is irrelevant to the hot cracking susceptibility in the weld fusion zone, but does affect this susceptibility in the heat affected zone (HAZ). More thermal cycles correspond to larger hot cracks in the HAZ, especially in the weld metal HAZ. The hot cracking susceptibility of materials increased with augment strain in both the fusion zone and the HAZ. Cold working of the materials can reduce their hot cracking susceptibility. The hot cracking susceptibility of 7075-T6 aluminium alloys is higher than that of 6061-T6. There was significant Cu segregation in the HAZ of 7075-T6 aluminium alloy, resulting in a higher susceptibility to hot cracking in this zone.     

A级船板冷加工开裂原因及解决途径

通过对A级般板进行化学成分、金相组织、拉伸性能、冲击性能、宽冷弯、落锤撕裂等试验,对A级船板在低温环境下冷加工过程中出现的开裂(冷脆)进行了分析。指出A级船板的冷脆开裂与其本身较差的冲击性能及火焰切割产生的淬硬组织有关;应在船板的生产过程中采取有效的质量控制措施,保证A级船板的性能在符合标准的技术要求的同时,具有良好的纯净度,以保证冷加工性能,满足船舶生产的需要。