Characteristic hot-forging defects in porous powder blanks of stepped shape

Conclusions A constriction is a characteristic HF defect of stepped blanks produced by nonsynchronous upsetting. Its size grows with increasing width of the clearance between the blank and the tool, with decreasing blank density, and with increasing step height. Constriction formation can be prevented by ensuring that the actual stepped parts and blanks have identical fillets in the transition zones, whose radii are not less than three times the anticipated constriction size.Translated from Poroshkovaya Metallurgiya, No. 9(309), pp. 6–9, September, 1988.     

Strengthening and toughening treatment of steel used as the material of multistation progressive dies

The Cr12MoV steel was chosen as the material of multistation progressive dies, and its impact toughness and hardness were measured, following different heat treatments. Based on experimental results, a practical technology carried out in vacuum is recommended as the strengthening and toughening treatment for these dies: 980°C oil pre-quenching, oil quenching again at 980°C, final tempering at 200°C for 1 hour, and then air cooling. This treatment makes the steel have fine austenitic grains and carbide particles, and thus leads to good combination of strength and toughness such that the service life of the dies is increased.     

Thermomechanical fatigue of dies for hot stamping

A method is proposed for calculating the fatigue life of dies used in hot stamping. Failure is assessed in terms of the strain and kinematic factors. Thermocyclic weakening is taken into account in determining the accumulated plastic strain. A special subprogram permits prediction of the number of cycles to die failure on the basis of finite-element modeling of tool–blank deformation.     

New slag-forming mixture for ladle treatment of steel

The components of a slag-forming mixture for the ladle treatment of steel are considered. The ratio of the mixture components is calculated, and the main characteristics and thermophysical properties of the mixture at high temperatures are determined.     

New developments for vacuum coating of steel strips

Vapor deposited coatings onto strip steel are a promising alternative as functional layers for corrosion protection or high abrasion resistance.Conventional coating systems have some limits regarding environmental compatibility,the range of coating materials and application properties. Physical vapor deposition(PVD) is an environment-friendly technology and enables nearly unlimited material and process variety.Electron beam high-rate evaporation with deposition rates up to some micrometers per second is ...     

New waterborne epoxy system for the corrosion-protection of steel

For its poor film forming and water-resistance properties,waterbome epoxy system is not applied for the protection of steel.The main reason for these problems is that the emulsifier of the emulsifying efficiency is not high while can not be separated out easily.Now,in terms of the use of newly synthesized emulsifiers to improve these two shortcomings,a new system was developed.Compared with solvent-based coatings,this new waterbome epoxy system's corrosion resistance was found close to the solvent-based ...     

瓷介电容器坯片干压成型用模具的选材与应用

为保证瓷介电容器坯片成型模具具有优良的使用性能，根据模具的常见失效形式分析并结合生产实际，应重点依据该模具的高硬度和高耐磨性进行模具用材的选材．经试验和分析选用YG15硬质合金．     

新时代 新钢铁

在全球钢铁业步入后危机时代之际,刚刚走出低谷的宝钢意识到钢铁行业的发展模式即将面临深刻的变革,甚至是革命。绿色钢铁是宝钢履行社会责任的执着追求。在长期的生产经营和市场竞争中,宝钢选择了技术创新与绿色钢铁的低碳之路,提出了环境经营的三大任务,同时把环境经营理念融入到企业经营管理的全过程,用成本的力量和全生命周期评价的观点重塑价值体系,化解资源环境压力,塑造钢铁的崭新社会角色。     

New age,new steel

Baosteel,which has just recovered from the global economic downturn,is deeply aware of the need for reforms,even revolutions,in the development of the steel industry."Green"steel is an ultimate goal for Baosteel to fulfill its social responsibilities.Learning from its long-term business operation and market competition,Baosteel has chosen technological innovation and built a low-carbon road to achieve"green"steel.It has also raised three tasks of"environmental operation"and endeavors to incorporate"environmental operation"into normal business operation,reestablishing its value system based on costs and lifecycles,reducing pressure on the environment and butiding a brand new role for iron and steel.