25Cr_2Mo_1V钢螺栓在长期高温高压下脆化机理的研究

通过对已脆化的２５Ｃｒ２Ｍｏ１Ｖ钢螺栓及经恢复热处理后的螺栓的金相及电子显微分析,阐述了２５Ｃｒ２Ｍｏ１Ｖ钢在长期高温高压下工作发生脆化的原因,讨论了恢复热处理对脆化螺栓恢复性能的作用     

XCQ-16车桥管热处理后组织异常原因分析

通过对车桥管XCQ-16热处理金相组织进行分析,发现热处理后的XCQ-16的组织异常、晶粒度粗大,造成该问题的原因是热处理过程控温不当所致.根据材料使用要求,给出了XCQ-16的热处理工艺.     

17-4PH马氏体不锈钢350℃长期时效脆化研究

采用光学显微镜(OM)、扫描电镜(SEM)、硬度测定以及示波冲击试验(instrumental impact test)研究了17-4PH马氏体不锈钢在350％：长期时效过程中显微组织、硬度、冲击韧性以及断口形貌的变化规律。结果表明：该马氏体不锈钢在350℃长期时效的过程中，随着时效时间的延长．其硬度升高，并在时效9000h时达到最大值；其裂纹萌生功(Ei)，裂纹扩展功(Ep)和总冲击功(Et)都随时效时间的延长而逐渐下降。根据示波冲击曲线获得了17-4PH马氏体不锈钢的动态断裂韧性Ktd，其动态断裂韧性也表现出和Ei，Ep及Et相类似的变化规律。该不锈钢的夏氏V型缺口(Charpy V-notch)冲击试样断口形貌随着时效时间的延长由韧窝断裂为主向准解理断裂和沿晶断裂为主变化。     

82B线材脆性断裂原因分析

82B线材在终轧后冷速过快导致表层出现马氏体是引起脆性断裂的原因之一.心部成分偏析导致奥氏体过冷,从而使马氏体出现在轴心部位,在拉拔过程中轴心马氏体断成竹节状,变成脆性断裂的裂纹源.大型脆性的夹杂物也是引起线材脆性断裂的起源.     

材料脆化对汽轮机组启动预热和超速试验温度的影响

分析了长期服役汽轮机转子产生的材料脆化现象，提出了老机组的启动预热温度和超速试验温度应以转子的脆性转变温度变化量△FATT为依据进行制定，才能预防转子的脆性破坏，确保老机组的安全可靠运行。     

冷轧单、双机湿平整剂的研制

针对武钢冷轧厂对湿平整剂应具有多种功能的要求,对选择的数10种添加剂进行了单独和复合作用性能试验,筛选出羧酸盐、脂肪族胺盐、杂环类有机物、安息香酸盐等高分子化合物水溶性防锈剂、聚氧乙烯非离子表面活性剂和脂肪酸盐阴离子表面活性剂为清洗添加剂以及低聚性高分子有机化合物作为成膜剂.结果表明,研制的YX-3湿平整剂不含亚硝酸盐,用于冷轧钢板、镀锌钢板的防锈性优于英国同类产品,具有优良的清洗性、适宜的润滑性,并与精整工序静电喷涂防锈油相容,在单、双机湿平整机组均能适用.     

平整机张力控制系统的改造

结合广州金莱冷轧带钢有限公司的生产实际，对平整机张力控制系统进行改造．着重介绍了改造后的平整机张力控制系统的构成及设计考虑．改造后工艺流程合理，带钢表面质量大大提高．     

Improvement on strip flatness of cold temper mills by modifying roll contour shape

A study on roll gap profile (strip profile) control was accomplished in a 1700 mm single-stand temper mill. Some critical problems such as the deviation of work roll contour caused by grinding and wear, the effectiveness of work roll bending were discussed. Using a finite element model, the effects of roll contours (ground and wear) on strip profile were investigated. The roll bending effect on strip thickness was also analyzed. It is pointed out that there are some special features of flatness control in the temper mill: during temper rolling, roll deformation is slight due to small rolling load, and the loaded roll gap profile mainly depends on work roll contour, while the backup roll has a little effect on gap crown; the effect of bending force on gauge can not be ignored due to the coupling between flatness control and gauge control. A new roll contour arrangement adaptable to the mill was presented and has been put into practical production. The application of the new set of rolls showed some good results: larger crown control range of work roll bender, higher rolling stability, better strip profile and flatness quality.     

Effects of heat treatment on structures and properties of high speed steel rolls

The effects of quenching temperature, cooling pattern, temper temperature and temper times on the structure and properties of high speed steel (HSS) rolls have been investigated. The results show that, when the quenching temperature is lower than 1050℃ the hardness of HSS increases with the quenching temperature increasing in oil cooling, but when the quenching temperature exceeds 1100℃ the hardness decreases. In the conditions of salt bath cooling and air cooling, the effect of quenching temperature on the hardness is similar to the above law, but the quenching temperature obtaining the highest hardness is higher than that in oil cooling. When the temper temperature below 350℃ the hardness of HSS has a little change, when above 475℃ the hardness will increase with the temper temperature increasing, and the highest hardness is obtained at 525℃. When the temper temperature continues to increase, the hardness decreases. Twice temper has little effect on the hardness, but three times temper decreases the hardness. HSS in air cooling has lower hardenability, oil cooling can easily produce crackle, and HSS quenching in salt bath has high hardenability and excellent wear resistance.     

Secondary work embrittlement of cold-rolled 05CuPCrNi sheet at low temperature

Due to the rapid development of China's rail transportation equipment manufacturing industry and related international distribution,important material suppliers such as Baoshan Iron Steel Co.,Ltd.carries on investigating the stability of material under extremely cold conditions.In this study,mechanical properties and secondary work embrittlement of weathering steel 05 CuPCrNi were tested at low temperature.Compared to the mechanical properties at room temperature,the yield and tensile strength increase slightly with decreasing temperature.However,the variation of elongation is not obvious.The experimental results also show that the secondary work embrittlement transition temperature of 05 CuPCrNi is lower than-60 ℃.These results provide the basis for the use of this train body material in extremely cold regions.