温度、应变率和晶粒对Mn18Cr18N钢高温塑性的影响

通过拉伸热模拟试验研究了温度、应变率和晶粒尺寸对Mn18Cr18N高氮奥氏体不锈钢高温塑性的影响。结果表明：在800℃~1 200℃温度范围内,Mn18Cr18N高氮奥氏体不锈钢的塑性随温度升高而升高,1 200℃时达到最好,然后开始下降;应变率通过再结晶的作用而影响塑性;当温度低于1100℃时,细晶粒尺寸材料的塑性优于粗晶粒尺寸,而温度高于1 100℃时中等晶粒尺寸材料塑性最好。     

1Cr18Ni9Ti钢低温退火强化研究

本文研究了１Ｃｒ１８Ｎｉ９Ｔｉ奥工体不锈钢经预冷变形后性能随低温退火的变化规律。结果表明，低温退火后强度及其弹性极限显著提高。     

航天用1Cr15Ni4Mo3N不锈钢棒材研制总结

1Cr15Ni4Mo3N是一种半奥氏体沉淀硬化不锈钢，与俄罗斯牌号эп310щ，美国牌号AM355很相近。我们知识：半奥氏体沉淀硬化不锈钢的特点，是在成分区间可借热处理工艺控制马氏体相变温度，使钢在成型或设备制造、部件过程中处于奥氏体组织状态。从而使钢具有奥氏体不锈钢的工艺特性，随后通过马氏体相变中沉淀硬化，使钢又具有马氏体不锈钢高强度和高韧性的特点，由于这个特点，这种钢用于某种航天用武器涡扇发动机的风扇轴，风扇轴为该武器的关键部件之一。     

0Cr21Ni5Ti双相不锈钢超塑成形研究

在ＧＬＥＥＢＬＥ１５００热／力模拟实验机上首次对０Ｃｒ２１Ｎｉ５Ｔｉ双相不锈钢进行了超塑性能研究，并获得了良好的超塑性能，同时确定了其超塑性成形最佳工艺参数，癫狂是出的最佳工艺参数应用于超塑性气压胀形工艺，在１０００ｋＮ超塑性成形机上一次整体成形出由０Ｃｒ２１Ｎｉ５Ｔｉ钢制造的一种带有侧凸的复杂零件。     

1Cr18Ni9Ti钢应力腐蚀破裂倾向实验研究

通过Ｕ形试件在４２％ＭｇＣｌ２沸腾溶液中的浸泡实验，探讨了１Ｃｒ１８Ｎｉ９Ｔｉ钢在供货、敏化和固溶三种状态下的应力腐蚀破裂倾向及碘离子的缓蚀作用。结果表明：①试件在固溶态时其应力腐蚀破裂倾向最小．供货态最大，敏化态居中；②碘离子对三种状态下的应力腐蚀均有显著的缓蚀作用。     

0Cr18Ni9奥氏体不锈钢在低浓度氯化钠溶液中的裸金属钝化特性

设计了研究０Ｃｒ１８Ｎｉ９奥氏体不锈钢裸金属钝化率的试验。分析其钝化曲线,指出０Ｃｒ１８Ｎｉ９奥氏体不锈钢在１０００ｍｇ／Ｌ ＮａＣｌ溶液中的钝化曲线满足ｉ（ｔ）＝ｉ０ｅ＾－β·ｔ关系,并引用钝化时间的概念解释腐蚀疲劳ｄａ／ｄＮ￣ΔＫ曲线在较低频率下基本重合的现象。     

节镍奥氏体不锈钢Cr18Mn6Ni4N的组织及性能

为节约镍资源,研究了不同成分17.8~19.1%Cr,3.93~6.05%Mn,3.58~4.62%Ni,0.32~0.42%N节镍型奥氏体不锈钢固溶后的力学性能和耐蚀性能,以期获得可替代304不锈钢的新钢种。结果表明:Cr18.4Mn5.98Ni4.62N0.42不锈钢的力学性能和耐蚀性能与304不锈钢相当。分析了该成分不锈钢时效处理后的组织演变规律、冷变形过程中奥氏体稳定性及形变诱发马氏体相变过程。结果表明:800℃是Cr2N相析出的鼻尖温度,随着时效时间的增加,析出相首先以颗粒状形貌沿晶界析出,而后以胞状析出方式向晶内生长。冷轧压下率18.5%时尚未发现形变诱发马氏体组织,随着变形量增大,片层状ε'马氏体含量先增加后减少至消失,而板条状α'马氏体含量逐渐增多,相对磁导率增加,但其奥氏体稳定性远高于304不锈钢。可见,Cr18.4Mn5.98Ni4.62N0.42不锈钢可替代304不锈钢。     

Semi-solid slurry preparation and rolling of 1Cr18Ni9Ti stainless steel

The preparation and rolling of the semi-solid slurry 1Cr18Ni9Ti stainless steel were researched. The experimental results show that when stirred for 2-3 min under the given test condition, the semi-solid slurry with about 50%-60% (volume fraction) solid and the spherical primary austenitic grains in the size of 100-200μm can be obtained, and it is easy to be discharged from the bottom little hole of the stirring chamber. The semi-solid slurry of 1Cr18Ni9Ti stainless steel can be rolled into the given plate successfully. However, the solid phase and liquid phase are easily separated in the rolling process, so that the solid primary austenitic grains are concentrated in the center and the liquid phase is near the edge of the rolled plate. The strengths of the plate rolled in the semi-solid state are higher than that of the traditionally repeated hot-rolled plate of 1Cr18Ni9Ti stainless steel.     

离心机用0Cr18Ni9不锈钢腐蚀失效分析

螺旋卸料沉降式离心机具有连续进料、螺旋推进、高速运转等特点.卧式螺旋卸料沉降式离心机已经在农业、化工、轻工等部门广泛应用.作为离心式分离设备,其高速旋转的转鼓能产生极大的离心力,以完成各种物料的液-固及液-液分离.作为核心部件的转鼓必须满足3个条件：耐腐蚀、高强度及低能耗.只有三者兼备,才能保证离心机的使用性和安全性.同时,为保证焊接区域的整体性和使用的稳定性,应使用合理的焊材和焊接工艺.     

Superplastic deformation of commercial 00Cr22Ni5Mo3N0.17 duplex stainless steel

The superplastic behavior of a commercial duplex stainless steel has been studied by means of isothermal hot tensile testat temperatures of 850-1050℃ for the initial strain rates ranging from 3×l0-4 s-1 to 5X10-2 s-1. At 960℃, the best superplastic de-formation that caused the maximum elongation greater than 840% was obtained for an initial strain rate of 1.2×10-3 s-1. At 850℃, thebest elongation 500% was achieved for an initial strain rate of 2.5×10-3 s-1. During the deformation in higher temperature region,coarse γ grains formed during the prior treatments were broken into spherical particles, resulting in a homogeneous dispersion of γparticles within the δ-ferrite matrix. However, at lower temperatures between 800 and 950℃, the σ phase was formed through theeutectoid decomposition of δ→γ+σ, resulting finally in the stable equiaxed micro-duplex structures with δ/γ and γ/σ, respectively.The precipitation of the σ phase played an important role in improving the superplasticity at 850℃. The strain-rate sensitivity coeffi-cient, m-values, were also determined by the strain rate change tests. The microstructure studies show that the superplastic processoccurs mainly by the local work hardening and the subsequent dynamic recrystallization and a grain boundary sliding and grain switching mechanism.     

0Cr18Ni9不锈钢焊接温度场的数值仿真

基于有限元软件SYSWELD对不锈钢0Cr18Ni9平板TIG焊的温度场进行三维动态模拟,得出了瞬态温度场分布图和特征点的热循环曲线,同时也得出了焊缝上任一点的温度变化与相变的关系.与文献资料比较表明,所建立的数值模拟仿真模型可以较好的模拟焊接温度场,为研究焊接过程中的应力应变和减少焊接应力与变形提供了参考依据.     

50Mn18Cr5钢护环冷扩开裂分析

为解决材料为50Mn18Cr5N的护环在冷扩时成功率低的问题,对其中两件护环取样,分别做化学成分、力学性能、低倍、高倍、气体、电镜和电解夹杂含量检验,进行失效分析,找出了在冷庳时成功率低的原因,最后得出结论：①护环开裂与材质质量无关;②技术和管理是生产优质产品必不可缺少的两在保证。     

激光冲击强化对2Cr13不锈钢腐蚀疲劳性能的影响

通过残余应力测量、腐蚀疲劳试验和疲劳断口形貌观察,研究了不同激光冲击层数对2Cr13不锈钢腐蚀疲劳性能的影响。试验结果表明,LSP会在2Cr13不锈钢表面产生高幅残余压应力,且表面残余压应力值随LSP冲击层数的增加而增加。与未强化试样相比,LSP试样的腐蚀疲劳寿命提升,且随LSP冲击层数的增加而提高;LSP试样的腐蚀疲劳裂纹扩展速率降低,且随LSP冲击层数的增加而降低。经分析,未强化试样疲劳断口形貌比较平坦,二次裂纹较少;LSP试样由于表面产生了较高的残余压应力,有效抑制了腐蚀疲劳裂纹的扩展,最终断口表现出河流花样形貌。     

铸态0Cr17Mn14Mo2N双相不锈钢加热时元素的分配

研究了铸态双相不锈钢在高温加热时各元素在铁素体和奥氏体两相中的重新分配，结果表明：铬元素在两相中的分配比例受温度的影响不大，而钼元素在温度降低时倾向于分配到铁素体中，锰元素在温度升高时在奥氏体中的分布稍多一些。     

薄壁1Cr18Ni9Ti奥氏体不锈钢的焊接试验

采用钨极氩弧焊的方法,对0.8 mm厚的1Cr18Ni9Ti奥氏体型不锈钢板实施焊接,并通LOM,SEM方法对焊接接头组织及断口形貌进行观察及分析;利用显微硬度计、电子万能拉伸机测量了焊接接头的力学性能.结果表明,通过手工钨极氩弧焊,采用直流正接接法(焊接电流为20 A,焊接速度为20 m/h)能够获得外观平整、组织均匀、力学性能满足要求的焊接接头.     

Hydrogen trapping in high strength 0Cr16Ni5Mo martensitic stainless steel

Hydrogen trapping behavior has been investigated by means of thermal desorption spectroscopy(TDS) for a high strength steel after it was tempered at the temperatures of 430 °C, 500 °C and 520 °C, respectively. The loss of ductility was characterized by slow strain rate test(SSRT) and microscopic observation. It shows that with hydrogen charging the fracture feature transfers from ductile to brittle, resulting in the loss of ductility. Undeformed microstructure immediately beneath the fracture surface in charged specimen corresponds to badly ductility compared to the obviously streamline plastic deformation in uncharged specimen. The activation energies for the peaks present in the TDS analysis are calculated for all tested steel and the activation energies for all temperature peaks are similar, corresponding to the similar types of hydrogen traps.