新型预硬塑料模具钢调质工艺研究

通过端淬试验及调质处理试验室模拟试验,对P20和718预硬型塑料模具钢的淬透性及调质工艺进行了研究和探讨.结果表明:P20和718的淬透性均较高,718比P20淬透性更高,更适合制作大型塑料模具;P20和718的最佳调质工艺参数为860℃淬火,560～590℃回火.     

圆坯连铸GCr15SiMn的成分偏析和接触疲劳寿命研究

利用金属原位分析技术和钻孔化学分析方法对高淬透性轴承钢GCr15SiMn的Φ450 mm连铸圆坯和Φ130 mm圆钢的C、Si、Mn、Cr元素横截面的分布情况进行分析。采用推力片式接触疲劳试验机进行了材料的接触疲劳寿命测试。结果表明：GCr15SiMn连铸圆坯C元素的偏析倾向较大,易产生中心正偏析,而Cr、Si、Mn元素的偏析倾向较小。通过采取稳定低过热度浇铸、三段强电磁搅拌等措施,铸坯的中心碳偏析得以改善。采用(1240±20)℃×5 h高温扩散、初轧首道次变形量≥90 mm大变形轧制的Φ130 mm圆钢的碳偏析可以得到进一步的改善,试验钢在5.3GPa高应力负载下的接触疲劳额定寿命L₁₀达到3.58×10⁶次,接近电渣重熔钢的水平。     

Calculated hardenability for improved consistency of properties in heat treatable engineering steels

Hardenability is one of the most important parameters controlling the heat treated properties of engineering steels. It affects the consistency of response for microstructure, hardness, strength, toughness, and dimensional change (distortion). This study illustrates that a major benefit of controlling hardenability is improving the consistency of dimensional distortion resulting from heat treatment. To facilitate the supply of steels to hardenability limits, especially restricted hardenability, a new technique was developed for the prediction of Jominy hardenability from chemical composition. The technique, termed the “Database Method,” uses measured Jominy hardenability and chemical composition data, contained in a database, to calculate the hardenability for a query composition. Using up to ten known steels, selected from the database with compositions closely matching that of the query steel, a small adjustment is made to the measured hardenability of each known steel allowing for the small difference in composition between the query and chosen steel. The final calculated result for the query steel is taken as the average of the various estimates. The basis of the Database Method is explained, and the advantages are illustrated for selecting engineering grades.     

4．5Ni钢淬透性试验研究

通过４．５Ｎｉ钢淬透性曲线、等温转变曲线及常规力学性能试验，研究了４．５Ｎｉ钢的淬透性；同时分析了合金元素对淬透性的影响；并用临界冷却速度预测了厚板能否淬透。研究结果表明，由于合金元素的交互作用，４．５Ｎｉ钢的淬透性优良，不但８０ｍｍ厚板可以淬透，而且只要严格控制化学成分，同时提高淬火剂的冷却强度，厚度不大于１００ｍｍ的板材也能淬透。     

石油储罐用调质高强钢中铬的机理研究

通过对低碳合金钢中加入cr元素,采用不同的保温时间下,cr对低碳合金钢调质后性能的影响研究,并选择不加cr的相同成分的合金钢与之做对比。通过金相组织观察发现cr能够有效地提高低碳合金钢的淬透性,淬火后即使钢板的芯部也能获得贝氏体组织。     

Development of a New Kind of High Strength Spring Steel

A new kind of high strength, high toughness and high plasticity spring steel has been developed. The strength, the reduction of area and the elongation of the steel are all higher than those of the steel 60Si2CrVA. The decarburization resistance and the sag resistance are also higher than those of the steel 60Si2CrVA. It has good hardenability, and is suitable for making springs with big cross section. The bogie springs made of this kind of steel have passed 2×106 cycles without broken under the conditions of maximum stress of 906 MPa and the minimum stress of 388 MPa.     

高强度船板NVD(E)420钢板的研制开发

介绍了高强度船板NVD(E)420的生产工艺及性能,对钢板的成分-淬火组织及性能进行了研究。通过合理的低成分设计并结合现场生产经验,研究了工艺参数对力学性能的影响,找出合理的工艺参数,得到良好的实物性能,为在该领域向更高级别、更大厚度船板的开发提供了技术储备。     

Effects of B on microstructure and hardenability of resistance seam welded HSLA linepipe steel

Abstract

The effects of B on the microstructural and mechanical characteristics of resistance seam welded high strength low alloy linepipe steel were investigated at different regions, such as weld, heat affected zone (HAZ) and base. Because most of the solute B atoms were already precipitated as iron borocarbides and iron borides in as welded steels, the improved hardenability was not observed regardless of the observed regions. The amount of dissolved B precipitates increased with austenitising temperature, and the pre-existing B precipitates were fully dissolved at 950°C for 180 s. The segregation of solute B atoms into austenite grain boundaries was more marked at higher austenitising temperatures, and the segregated solute B atoms greatly increased the hardenability of the austenitised pipes, resulting in hard microstructures like bainite and martensite. The B addition also effectively compensated for the deteriorated hardness at the weld and HAZ of the tempered specimens, although B atoms were precipitated during tempering.     

直缝焊管轧机轧辊球铁材质研究

研究了轧辊新材质———铜钒钛球铁。对石墨球化、铸态基体组织、力学性能、淬硬性、淬透性和滚、滑动摩擦磨损特性的系统研究表明，合金铜钒钛球铁是一种价格低廉、淬透性、耐磨性比ＧＣｒ１５钢更好的轧辊材质，更适合替代ＧＣｒ１５钢材质制造中、小截面轧辊     

10CrNi3MoV 30C对称双球扁钢淬透性试验研究

通过球扁钢淬透性的测定以及对中频淬火态横截面硬度分布、金相组织与晶粒度的观察评定 ,研究了 10CrNi3MoV 30C双球扁钢的淬透性。结果表明 ,10CrNi3MoV 30C球扁钢的淬透性良好 ,用端淬试验来研究 10CrNi3MoV 30C球扁钢的中频淬火是可行的。