Effect of cooling condition on deformation of continuously cast stainless steel 304

This work investigated the effect of the cooling condition on the deformation that was found for continuously cast stainless steel 304 slabs. The transient heat-transfer finite element analysis under various cooling conditions yielded temperature distributions within the slab, which were then used for subsequent calculations of the deformed shape. The asymmetric cooling condition in a cooling pit induced non-uniform and asymmetric thermal gradients with elapsed time. The non-zero final deflection and the reversal of curvature for the slab during cooling were attributed to the combined effect of asymmetric temperature profile and inelastic material property. Parametric studies revealed that a slab material of a low thermal conductivity or yield strength resulted in an increase for final deflection. The present analysis explained the physical cause of the deformation reasonably well.     

Effect of structure on deformation and failure of cast steel

Conclusions Quenching and tempering of cast ferritic — pearlitic steels refines the grains and makes it possible to increase the yield strength and the stress at which crack formation begins with almost no change in hardness, to improve the ductility and toughness at positive and negative temperatures, and to increase the fatigue limit of the steel.V. Ya. Chubar' Zaporozh'e Machine Construction Institute. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 5, pp. 74–75, May, 1975.     

连铸滚珠轴承钢的质量

介绍夹杂物的种类和大小对滚珠钢接触疲劳的影响.对含Al和不含Al两种滚珠钢的质量进行对比.描述了神户、POSCO、Saar几家钢厂生产滚珠钢的情况.讨论钢中MgO·Al2O3夹杂的来源.     

钙处理对连铸钢浇铸性能的影响

分析钙处理对连铸钢浇铸性能的影响，为了改善浇铸性能，应向钢中加入适量的钙，形成液态的铝酸钙。钙处理不当时不仅影响钢水的浇铸性能，而且还会影响钢水在结晶器内的凝固行为。     

初始成形温度对超高强钢热冲压件力学性能的影响

研究了高温钢板转移时间与初始成形温度之间的关系,分析了初始成形温度对超高强钢板热冲压件力学性能的影响规律。结果表明,随着板料转移时间的增加,初始成形温度降低,两者之间为线性关系;在一定范围内随着初始成形温度升高,热冲压件的力学性能增加,当初始成形温度高于800℃时,热成形件的力学性能基本不变;形变促进奥氏体晶粒细化,获得相对细小的马氏体组织,热成形件力学性能优于非变形钢板。     

Changes in the state of heat-resistant steel induced by repeated hot deformation

This work deals with the problems of structural regeneration by thermal restoration treatment (TRT). These include the lack of a structural sign showing that TRT is possible, a consensus on TRT modes, the data on the necessary relaxation depth of residual stresses, or criteria of structural restoration. Performing a TRT without solving these problems may deteriorate the properties of steel or even accelerate its destruction. With this in view, the purpose of this work is to determine experimentally how the residual stress state changes under thermal and mechanical loads in order to specify the signs of the restoration of structure and structural stability. The object of this research is unused 12Cr1MoV steel that has been aged naturally for 13 years. Using X-ray dosimetry with X-ray spectral analysis, we study the distribution of internal residual stresses of the first kind during the repeated hot deformation. After repeated thermal deformation, the sample under study transforms from a viscoelastic Maxwell material into a Kelvin-Voigt material, which facilitates structural stabilization. A sign of this is the relaxation limit increase, prevention of continuous decay of an α-solid solution of iron and restoration of the lattice parameter.     

Structure and properties of continuously cast low-carbon steel as a function of the reeling temperature

Investigation of continuously cast low-carbon aluminum-killed steel has great practical importance. Its structure and properties depend on the reeling temperature after hot rolling. After reeling at a low temperature the steel exhibits a capacity for deep drawing, whereas after reeling at a high temperature it is suitable for enameling.Translated from Metallovedenie i Tetmicheskaya Obrabotka Metallov, No. 8, pp. 23 – 24, August, 1996.     

300M钢的热变形行为及其变形组织演变研究

基于热压缩实验,对300M钢在应变速率为10s-1下的热变形行为及其变形组织演变进行了研究。结果表明:在试样高度压下量为50%,变形温度为700～750℃时,300M钢的应力-应变曲线呈流变失稳型,且变形组织出现绝热剪切;当变形温度为800～1000℃时,300M钢的应力-应变曲线呈双峰不连续动态再结晶型,且热变形过程出现了两轮动态再结晶;当变形温度为1050～1180℃时,300M钢的应力-应变曲线呈单峰不连续动态再结晶型,且热变形过程只发生了一轮动态再结晶。     

Changes in the density of steel during plastic deformation and annealing

Conclusion The volumetric method was used to study the formation of microcracks during plastic deformation of annealed and normalized steel 70. It was found that the number of microcracks formed increases with the coarseness of the original structure. Defects occurring with substantial plastic deformation of annealed steel with a structure of coarse lamellar pearlite are healed by brief heating to temperatures above 1100°.Institute of Metal Physics, Academy of Sciences of the USSR. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 1, pp. 21–23, January, 1971.     

有关连铸坯质量的几个问题

对连铸坯为何不能生产沸腾钢、减少高碳钢连铸小方坯中心偏析的两种相反的思维和优化的钢包渣进行了讨论。     

Influence of deformation and annealing on the structure of continuously cast BrOTsS5-5-5 bronze

Conclusion Continuously cast billets of BrOTsS5-5-5 bronze have quite high internal stresses occurring as the result of formation of the casting, which are added to the deformation stresses, and lead first to the formation of a twinned structure (with =30%) and then to failure of the material (with =40%). In comparison with permanent mold ones the structure of such billets is coarse grained with strictly oriented axes of the dendrites in the direction of the solidification front.All-Union Scientific-Research and Design Institute for Secondary Nonferrous Metallurgy. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 8, pp. 59–60, August, 1984.