高氮18CrMnB钢渗碳层淬透性及晶粒度的研究

本文研究了微量元素铝，氮及预先预热处理对高氮１８ＣｒＭｎＢ钢渗碳层淬透性及奥氏体晶粒长大倾向的影响，结果表明，微量元素铝，氮对高氮１８ＣｒＭｎＢ钢心体淬透性影响很大，而对渗碳层淬透性，特别是对渗碳表层淬透性影响较小，预先热处理对高氮１８ＣｒＭｎＢ钢渗碳层奥氏体晶粒长大倾向影响很大，不同预先热处理状态的高氮１８ＣｒＭｎＢ钢渗碳层奥氏体晶粒粗化温度对钢中微量元素铝，氮含量变化的敏感程度不同。     

攀钢汽车用优质钢的开发

介绍了攀钢用１２０ｔ大型转炉生产２０ＣｒＭｎＴｉ,４０ＭｎＢ,６０Ｓｉ２Ｍｎ,５５ＳｉＭｎＶＢ钢的工艺及性能。通过采用出钢前向钢包内加入钙基预脱氧剂,喂铝线,喂复合包芯线处理钢液,以及对铬铁合金化工艺进行改进等技术措施,解决了钢的成分控制问题,保证了钢才的淬透性和清洁度,生产出的２０ＣｒＭｎＴｉ,４０ＭｎＢ,５５ＳｉｍＮＶＢ等钢种为汽车用优质钢。     

氮含量对Cr18Mn18N无磁不锈钢力学性能、磁导率和组织的影响

探讨了Ｃｒ１８Ｍｎ１８Ｎ无磁不锈钢中氮含量对钢的力学性能、磁导性能以及组织状态的影响，研究结果表明，Ｃｒ１８Ｍｎ１８Ｎ钢中氮含量大于０．３１％时，组织才为全奥氏体状态，该钢氮含量的最佳区间为０．４％￣０．６％。     

含氮较高的18CrMnB渗碳硼钢研究

研究了酸溶铝和微量钛氮含量较高的１８ＣｒＭｎＢ钢奥氏体晶粒长大倾向、淬透性和力学性能的影响，加热温度对固溶硼含量的影响和冷却速度对钢中硼分布的影响，探讨了此类钢固定氮的必要性，并确定了固定氮方案。     

推土机几种铲刃钢耐磨性能研究

根据国内资源及使用要求．研制了３１Ｓｉ２ＣｒＭｏＢ及４０ＳｉＭｎＴｉ钢。并对３１Ｓｉ２ＣｒＭｏＢ、４０ＳｉＭｎＴｉ及６５Ｍｎ三种材料的耐磨性能，进行了装车对比试验。结果表明，由于采用“三同步”原则，保证了耐磨性能数据的可靠性、真实性及数据的完整性；４０ＳｉＭｎＴｉ钢由于钢中存在ＴｉＣ质点，因而耐磨性很高，比６５Ｍｎ钢高２４．３％～２６．１％，但材料的冲击性、塑性差；３１Ｓｉ２ＣｒＭｏＢ钢由于韧性、塑性好，抗回火软化性能好，耐磨性能比６５Ｍｎ钢提高２６．１％，该钢适用于大功率推土机；６５Ｍｎ钢合金含量少，成本低，适用于小功率推土机。     

稀土元素对热轧辊用钢60CrMnMo热疲劳性能的影响

本文研究了稀土元素对热轧辊用钢６０ＣｒＭｎＭｏ热疲劳性能的影响，同时对不同稀土含量的６０ＣｒＭｎＭｏ钢高温短时拉伸性能和硬度进行了比较。试验结果表明：稀土元素可明显提高６０ＣｒＭｎＭｏ钢的热疲劳寿命和塑性，抑制６０ＣｒＭｎＭｏ钢的循环软化，并得出稀土元素的合适含量为０．０５％－０．１０％。     

不同冶炼工艺对20CrMnTiH钢淬透性的影响

运用计算机回归处理方法,对不同冶炼工艺生产的２０ＣｒＭｎＴｉＨ钢进行统计分析,得出淬透性Ｊ９与化学成分的回归方程式,并对比得出采用ＥＢＴ＋ＬＦ工艺冶炼的２０ＣｒＭｎＴｉＨ钢淬透性高于电弧炉单炼的２０ＣｒＭｎＴｉＨ钢。     

CrMo新轴承钢的热处理工艺与性能

研究了铬轴承钢ＧＣｒ１５ＳｉＭｎ和新开发的Ｃｒ－Ｍｏ轴承钢的ＧＣｒ１５Ｍｏ和ＧＣｒ１６Ｍｏ的热处理工艺和性能。结果表明，ＧＣｒ１５Ｍｏ钢的淬透性低于ＧＣｒ１５ＳｉＭｎ多，但ＧＣｒ１６Ｍｏ钢的淬透性高于ＧＣｒ１５ＳｉＭｎ钢，ＧＣｒ１５Ｍｏ和ＧＣｒ１６Ｍｏ新钢种的机械性能和接触疲劳寿命均高于ＧＣｒ１５ＳｉＭｎ新钢种适合于制作重型机械用轴承。     

40Cr和20Mn2钢一次晶体的高温塑性及动态再结晶

用Ｇｌｅｅｂｌｅ １５００热模拟研究了原位熔化凝固的４０Ｃｒ和２０Ｍｎ２钢的应变速率对热塑性和强度的影响。用扫描电镜（ＳＥＭ）和光学显微镜（ＯＭ）分别观察了试验后试样的断口形貌和断口的附近区域的显微组织。试验结果表明，４０Ｃｒ和２０Ｍｎ２钢在７００－１３００℃温度范围的塑性随着应变速率的增加而提高。     

SUS316钢纯净度对耐腐蚀性能的影响

日本金属材料技术研究所在研究耐海水腐蚀不锈钢ＳＵＳ316试验中,对超高氮和高纯度ＳＵＳ316Ｌ不锈钢在坩埚中进行再熔炼制造出钢板(以下称ＣＣ钢)作耐腐蚀性能试验,提高了耐局部腐蚀性能。从市场购买的低硫ＳＵＳ316Ｌ圆钢(Φ55ｍｍ,以下称ＣＳ钢)为原料,其成分(%)0014Ｃ056Ｓｉ066Ｍｎ0026Ｐ0001Ｓ1378Ｎｉ1682Ｃｒ216Ｍｏ003Ｎ0003Ｏ,在Ａｒ气氛下使用熔剂ＣａＦ2熔炼成ＣＣ钢,明显降低Ｎ、Ｏ含量提高ＣＣ钢纯净度,其实际成分(%)0014Ｃ055Ｓｉ061Ｍｎ0023Ｐ<0001Ｓ1350Ｎｉ1630Ｃｒ210Ｍｏ001Ｎ00003Ｏ。ＣＣ钢经过锻造、热轧、冷轧后轧…     

不同铜含量含硼低碳钢的时效硬化

 研究了不同铜含量的含硼低碳钢的时效行为,对时效后的试验钢进行显微硬度测试,并用光学显微镜及电镜观察组织及析出物,分析时效工艺和硼含量对硬度及析出粒子的影响。结果表明：含铜钢的时效是析出硬化与组织软化作用相互影响的结果。随时效温度升高,析出峰值由双峰变为单峰及无峰值。添加微量硼可替代部分铜而硬度变化不明显,在稳定马氏体结构、推迟基体软化方面,复合添加硼和铜比单纯加铜更显著。     

Improving the creep properties of 9Cr-3W-3Co-NbV steels and their weld joints by the addition of boron

New ferritic steels with a controlled addition of boron have been developed recently for ultrasuper-critical fossil power plants. These steels possess excellent creep resistance compared to conventional steels like P91, P92, P122, etc., and this has been attributed to the delay in coarsening of the carbides during creep owing to partial replacement of carbon by boron in these carbides. However, the susceptibility of the weld joints of the boron-containing ferritic steels to type IV cracking, which significantly brings down the rupture life of the weld joints, has not been investigated so far. In the present work, the creep properties of recently developed 9Cr-3W-3Co-NbV steels with boron contents varying from 47 to 180 ppm and of their weld joints have been studied. Creep tests were carried out at 923 K in the stress range of 140 to 80 MPa. Specimens were examined for particle coarsening using field-emission scanning electron microscopy, and the boron content in the precipitates was estimated using field-emission auger electron spectroscopy (FE-AES). The grain size of the parent metal and the heat-affected zone (HAZ) were estimated using electron backscattered pattern (EBSP) imaging. Results showed that the creep properties of the steels with 90 and 130 ppm boron and of their weld joints are superior to those of the P92 steels and its weld joints. Further, no weld joints exhibited type IV cracking. No significant coarsening of the carbides was observed, not only in the parent metal but also in the HAZ of the steels with ≥90 ppm of boron. In addition to the delay in carbide coarsening, the large prior-austenite grain size of the parent metal and the absence of a conventional fine-grained HAZ (FGHAZ) in the weld joints also seem to have a beneficial effect on improving the creep properties of these steels and their weld joints.     

不同硼含量微合金钢的连续冷却相变行为

 利用热模拟试验技术对实验室制备的含硼微合金钢连续冷却转变形为进行了试验研究,利用光学显微镜研究冷却速度、变形对试验钢显微组织的影响,探讨了硼对转变行为的影响规律。结果表明：适量硼延缓多边形铁素体生成,有利于获得贝氏体组织;无硼及wB=00020%时,分别在1~25及05~25℃/s的冷速都能得到贝氏体组织;wB=00030%时,冷速在2℃/s 以上能得到贝氏体组织;与未变形相比,变形导致试验钢贝氏体冷速区间变窄。在同一冷速下,随硼含量增加贝氏体开始转变温度先降低再升高,显微硬度随硼含量增加先增加而后降低。     

The boron hardenability effect in thermomechanically processed,direct-quenched 0.2 Pct C steels

The segregation and precipitation of boron have been studied in thermomechanically processed 0.2C-0.6Mn-0.5Mo steels containing nominally 0, 10, 20, 50, and 100 ppm B. These steels were hot-rolled in the laboratory (in simulation of production multipass rolling), and their transformation behavior during subsequent water quenching was examined for different finish-rolling temperatures (980 °C and 870 °C) and quenching temperatures (730 °C to 950 °C). The results showed that in general, a “free” boron content of 10 to 20 ppm (which is similar to the levels used for conventional quenched-and-tempered steels) will provide a boron hardenability increment similar to that for conventional quenched-and-tempered steels. The delay time prior to quenching (over the range of 10 to 100 seconds) did not have a significant effect on hardenability except in the steels containing 50 or more ppm B. In these higher B steels, precipitation of borocarbides occurred along austenite grain boundaries with a resultant decrease in hardenability.     

Effect of composition and austenite deformation on the transformation characteristics of low-carbon and ultralow-carbon microalloyed steels

Deformation dilatometry has been used to simulate controlled hot rolling followed by controlled cooling of a group of low- and ultralow-carbon microalloyed steels containing additions of boron and/or molybdenum to enhance hardenability. Each alloy was subjected to simulated recrystallization and nonrecrystallization rolling schedules, followed by controlled cooling at rates from 0.1 °C/s to about 100 °C/s, and the corresponding continuous-cooling-transformation (CCT) diagrams were constructed. The resultant microstructures ranged from polygonal ferrite (PF) for combinations of slow cooling rates and low alloying element contents, through to bainitic ferrite accompanied by martensite for fast cooling rates and high concentrations of alloying elements. Combined additions of boron and molybdenum were found to be most effective in increasing steel hardenability, while boron was significantly more effective than molybdenum as a single addition, especially at the ultralow carbon content. Severe plastic deformation of the parent austenite (>0.45) markedly enhanced PF formation in those steels in which this microstructural constituent was formed, indicating a significant effective decrease in their hardenability. In contrast, in those steels in which only nonequilibrium ferrite microstructures were formed, the decreases in hardenability were relatively small, reflecting the lack of sensitivity to strain in the austenite of those microstructural constituents forming in the absence of PF.     

On the trueness of total boron contents of some certified reference steel samples

In order to obtain true values for the boron content of steel samples, the need for complete dissolution of all boron phases present in the steels is stressed and the importance of an appropriate calibration procedure is also emphasised. The results of international research by ECISS/TC20 using direct spectrophotometry with curcumin (pr EN 10 200) have been compared with those of the curcumin method after separation by 2-ethyl-1.3-hexanediol-chloroform extraction and those of the 1.1'-dianthrimide method after distillation of the boron methylester by means of an all-quartz apparatus. The results obtained were independent of the method of determination.     

硼含量对低碳钢耐蚀性的影响

 为考察不同硼含量低碳钢的腐蚀规律,利用盐雾腐蚀试验研究了不同硼含量低碳钢的腐蚀行为,结合X射线衍射（XRD）和傅里叶红外光谱（FTIR）对腐蚀产物进行了分析。试验结果表明：含硼低碳钢腐蚀速率与硼质量分数有关,硼质量分数0.002%试验钢腐蚀速率低于无硼钢,硼质量分数高于0.002%的试验钢腐蚀速率超过无硼钢,并且随硼含量增加,试验钢的腐蚀速率逐渐增加;阐述了硼的腐蚀机制。     

热轧工艺对20CrMnB奥氏体晶粒粗化温度的影响

研究了压下率，终轧温度及冷却速度对20CrMnB钢奥氏体晶粒粗化温度的影响。     

Overview no. 63 Non-equilibrium grain boundary segregation of boron in austenitic stainless steel-II. Fine scale segregation behaviour

A combination of TEM, FIM, AP and IAP has been used to study boron grain boundary segregation in austenitic stainless steels of the types 316L (with 40 ppm or with <1 ppm boron) and “Mo-free 316L” (23 ppm boron). High resolution segregation profiles were determined for cooling rates from 0.29 to 530°C/s for three starting temperatures: 800, 1075 and 1250°C. Boron grain boundary segregation was found after all heat treatments. The segregation behaviour was mainly of the nonequilibrium type after cooling from 1075 or 1250°C whereas equilibrium segregation dominated after rapid cooling from 800°C. The influence of the relative grain orientation on the amount of non-equilibrium segregation was small for general boundaries. However, no segregation was detected at coherent twin boundaries. The binding energy of boron to austenite grain boundaries was estimated at 0.65 ± 0.04 eV for both types of steels. The influence of the composition and boron content of the steels on the segregation behaviour is discussed and the experimental techniques used are presented.