热加工工艺对316LN奥氏体不锈钢晶粒度的影响研究

采用Zeiss Imager金相显微镜观察316LN奥氏体不锈钢微观组织形貌,研究了变形温度、变形率以及固溶温度对其晶粒度的影响。结果表明,随着变形温度和变形率的增加,显著促进了其动态再结晶的发生,有助于获得细化和均匀化的奥氏体不锈钢晶粒。锻造变形后钢板的晶粒度由小到大依次为表面>1/4处>心部,变形温度和变形量分别为1 050℃,30%时,变形后的晶粒度可达到6级左右。固溶处理对锻造后的钢板晶粒度控制具有均质化作用,结合Jmat-Pro计算分析固溶处理结果,固溶温度应控制在1 020～1 040℃范围内,温度过高容易导致晶粒过度长大,温度过低容易导致Cr2N相析出,影响钢板的塑性和耐蚀性能。     

板材加热和轧制过程奥氏体晶粒尺寸控制

在中厚板生产中,获得细小晶粒尺寸是制定生产工艺的基本出发点,坯料加热原始奥氏体晶粒的尺寸对后续轧制过程中奥氏体晶粒尺寸的变化有很大影响,热塑性轧制是奥氏体晶粒细化的主要工序,奥氏体冷塑性轧制可以进一步细化相变后的铁素体晶粒尺寸。结合文献中相关数学模型和中厚板实际生产过程中诸多影响因素,分别从坯料加热、热塑性轧制、冷塑性轧制过程3个方面,阐述了C-Mn钢奥氏体晶粒细化的影响因素及对相变后铁素体晶粒尺寸的影响。     

奥氏体不锈钢中厚板加热工艺优化

介绍了采用空气、煤气双蓄热式加热炉生产奥氏体不锈钢中厚板的加热工艺制度,通过对加热温度、加热制度、炉内空燃比、残氧量、板坯在炉时间的调整优化,解决了由于不锈钢自身特性及加热制度不合理导致的不锈钢表面裂纹、色差等质量缺陷。     

20MnVB钢奥氏体晶粒度控制的探讨

一、前言20MnVB 钢作为东风载重汽车后桥大模数齿轮材料,承受着较大的载荷。齿轮加工中需经过940～960℃渗碳淬火处理,这就要求材料在高温状态下具有晶粒不粗化倾向。第二汽车制造厂,根据齿轮生产和使用的需要,对20MnVB 钢的奥氏体晶粒度提出了严格的技术要求,即在960℃加热,保温     

20CrMo钢棒材轧制过程中奥氏体晶粒的控制

通过Gleeble-1500热模拟机对石钢生产的20CrMo钢轧材精轧阶段轧制过程进行模拟,研究了终轧温度、变形程度对奥氏体晶粒大小的影响,找出了理想的终轧温度和变形量.     

316L奥氏体不锈钢的氮合金化

采用金相显微镜、XRD、拉伸试验机及高低温冲击试验机等,并结合Thermo-calc软件计算研究了氮对316L奥氏体不锈钢微观组织、析出相、力学性能和耐点蚀性能的影响.结果表明:氮合金化能够抑制316L不锈钢中σ相和Chi相的析出,增加Cr2N的析出倾向,对奥氏体晶粒细化不明显;氮的添加能够提高316L不锈钢的室温强度和-100℃以上温度的夏比冲击功,降低-100℃以下的夏比冲击功,但对室温拉伸塑性影响不明显.此外,氮能够改善316L不锈钢的耐点蚀能力.     

中厚板轧制中的平直度控制技术

中厚板轧制中的平直度控制技术［日］吉井诚等１绪言近年来，用户为了节省工序，对中厚板的平直度以及尺寸精度要求更加严格，且从节能、缓和以节省工序为目的的换辊制度以及提高成材率方面来看，开发平直度、钢板凸度控制技术成为重要的课题。以往，在水岛制铁所的中厚板...     

中厚板轧制控制冷却技术

对控制冷却系统的选择提出一些分析意见。主要讨论以下内容：冷却方式、冷却设备型式的选择、冷却设备的位置、冷却设备的长度以及控制冷却技术的最新发展。     

微合金钢中板热轧时晶粒尺寸的模拟计算

通过Φ180mm× 2 0 0mm二辊实验轧机对成分 (% )为 0 0 5 3C 1 5 6Mn 0 0 4 6Nb 0 2 5Mo 0 0 14Ti 0 0 0 12B微合金化钢的轧制实验 ,验证了新建立的热轧板带晶粒尺寸的仿真模拟系统 ,得出晶粒尺寸的仿真计算值与实测值的相对误差≤ 8 3% ,并对该微合金钢 9道次 2 2 0 0mm× 14mm中板轧制时各道次钢板晶粒尺寸进行了计算。结果表明 ,精轧各道次均没有发生动态再结晶 ,在板厚 5 1 6mm轧至 2 2 0mm的 1～ 5道次 ,晶粒尺寸显著减小 ,由 4 5 μm降至 10 μm ,在板厚 2 2 0mm轧至 14 0mm的 6～ 9道次 ,晶粒尺寸减小不显著 ,由10 μm降至 7 5 μm     

Tribological Investigation of Effect of Grain Size in 304 Austenitic Stainless Steel

Stainless steels are widely used in a variety of engineering applications such as food appliances, surgical instruments, nuclear reactors and cryogenic applications. The properties of stainless steel are greatly affected by the grain size. The present study investigates the effect of grain size on sliding wear behavior of AISI 304 stainless steel. The sliding wear properties are measured using a Pin-on-Disc machine. Annealing heat treatment process varies the grain size of steel at 1100 °C. The wear test is performed on different grain sizes of AISI 304 steel at various sliding speeds under dry condition. The wear rate of the steels at different sliding distances is plotted as a function of grain size. The maximum wear rate is obtained at an intermediate grain size. It is noted that frictional force and temperature initially increases and then reaches the saturation plateau. The results are used to establish a correlation between the grain size and sliding wear properties of stainless steel. The present study is useful in enhancing the life of various components made of the stainless steel.     

Effect of Grain Size on Mechanical Properties of Nickel-Free High Nitrogen Austenitic Stainless Steel

The fine grained structures of nickel-free high nitrogen austenitic stainless steels had been obtained by means of cold rolling and subsequent annealing.The relationship between microstructure and mechanical properties and gain size of nickel-free high nitrogen austenitic stainless steels was examined.High strength and good ductility of the steel were found.In the grain size range,the Hall-Petch dependency for yield stress,tensile strength,and hardness was valid for grain size ranges for the nickel-free high nitrogen austenitic stainless steel.In the present study,the ductility of cold rolled nickel-free high nitrogen austenitic stainless steel decreased with annealing time when the grain size was refined.The fracture surfaces of the tensile specimens in the grain size range were covered with dimples as usually seen in a ductile fracture mode.     

奥氏体不锈钢302和304的轧制

由于奥氏体不锈钢加Ｔｉ后污染钢液,在钢中形成ＴｉＮ和Ｔｉ(ＣＮ)夹杂,国外含Ｔｉ奥氏体不锈钢的生产量很小(只占0.5%),所以不含Ｔｉ的302和304奥氏体不锈钢得到了广泛应用。302钢号相当于1Ｃｒ18Ｎｉ9,304钢号相当于0Ｃｒ18Ｎｉ9。1　302和304不锈钢的轧制特点(1)钢的导热性差,导热系数相当于低碳钢的27%,加热速度较慢,一般为130℃ｈ。(2)在900～1250℃时有良好的塑性,但热变形抗力很大,随着加工过程中温度的下降,变形抗力急剧增高,因而要控制终轧温度和变形程度,通常轧制时为使终轧温度不低于950℃,轧辊表面不浇冷却水,并控制最大相对压…     

热处理工艺对316H不锈钢中厚板力学性能影响研究

采用扫描电镜对316H钢中厚板冲击、拉伸试样断口进行观察,结果表明,冲击不合和屈服强度较低试样断口形貌均为脆性断裂,因断口上有大量富铬钼的σ相,严重影响了钢的塑性、韧性。分析了钢板在轧制及热处理过程中可能出现σ相的环节,对钢板热轧后的冷却速率,钢板固溶过程中的加热速度、保温温度、保温时间进行了一系列调整,调整工艺后生产的316H不锈钢中板厚度方向不再析出σ相,各个位置力学性能满足要求。     

中厚楔形板轧制的过程控制模型

提出了两阶段楔形板轧制的观点,并建立了楔形轧制的过程控制模型;运用负荷函数法结合循环迭代法进行了楔形轧制道次数及中间厚度的优化确定;在不改变楔形轧制优化的道次数的前提下,进行了楔形轧制阶段各道次的压下量优化重分配,优化了轧制规程.模拟仿真表明,该过程控制模型能够根据各种坯料规格及目标尺寸规格,很好地优化制定楔形轧制过程控制规程,可以为楔形板的实际生产提供一定的参考依据.     

Static Recrystallization Behavior of 316LN Austenitic Stainless Steel

The static recrystallization of 316LN austenitic stainless steel was studied by double-pass hot compression tests on a Gleeble-3500 thermomechanical simulator. The specimens were compressed at the deformation temperatures of 950, 1050, 1150 °C, strain rates of 0.01, 0.1, 1s^?1, strains of 0.1, 0.15, 0.2, and intervals of 1 — 100 s. The results show that the volume fraction of static recrystallization of 316LN increases with the increase of deformation temperature, strain rate, strain and interval, which indicates that static recrystallization occurs easily under the conditions of higher deformation temperature, higher strain rate and larger strain. Deformation temperature has significant influence on static recrystallization of 316LN. The volume fraction of static recrystallization could easily reach 100% at higher deformation temperatures. By microstructure analysis, it can be concluded that the larger the volume fraction of static recrystallization, the more obvious the grain refinement. The static recrystallization activation energy of 317 882 J/mol and the exponent n of 0.46 were obtained. The static recrystallization kinetics was established. The predicted volume fraction of static recrystallization is in good agreement with the experimental results.     

不锈钢连铸坯轧制中板工艺研究

分析了不锈钢连铸坯轧制中板的原理并进行了生产试验。试验表明，该工艺简单易行。     

核电用超纯316H奥氏体不锈钢锻件的质量控制

通过对成分计算、熔炼工艺和电渣渣系分析、均质化退火工艺试验等方法,对20 t EAF-AOD-LF-VD- Φ430 mm电极Φ 590 mm ESR锭-均质处理 Φ310 mm锻材流程生产的核电用钢超纯316H工艺进行研究。当成分 (/%)满足 0.042 - 0. 047C, ≤0. 55Si, 1.60-1. 80Mn,17.00 -17. 30Cr,12. 20 ~ 12. 40Ni,2. 50 ~ 2. 60Mo, ≤ 5 x 10^-6 H,≤ 30 x 10^-6 O, 0. 055 - 0. 070N 时,将 Φ430 mm 电极釆用 CaF₂ ： Al₂O₃: CaO = 60% : 30% : 10% 渣系电渣成 Φ590 mm锭,在1 200 ~ 1 250℃ 经过30 h均质化处理后,能够生产出符合标准的产品,实物夹杂物级别为A,C 0 级,B_细 0.5级 B_粗 0级,D_细1.0级,D_粗0~0.5级,Ds (0-0.5)级;铁素体含量≤ 0.5%。