Study On1CrMn2MoVTiB Non-Quenched And Tempered Plastic Mould Steel

The production of plastic mould steel has almost the same pattern of ingot-breakdown-rolling-pre-hardening and heat treatment. The shortcomings of this pattern are production link multiple, production cycle long, cost high, and it is a waste of energy when pre-hardening. This paper aims at the using of continuous casting billet to product steel plate which was rolled at wide and heavy plate mill. The steel plate can meet the properties of pre-hardened plastic mould steel P20with the process of controlled rolling and controlled cooling. It has a greater significance to achieve a greater efficiency and production scale.In this paper, composition design, controlled rolling and controlled cooling process and service properties were studied.The major achievements of the paper include:(1) Chemical composition of the non-quenched and tempered mould steel is successfully designed (mass%):C:0.10～0.13, Si:0.25～0.40, Mn:1.40～1.60, Cr:1.1～1.5, Mo:0.23～0.25, V:0.05～0.08, Ti:0.015～0.025, B:0.002～0.04.(2) Through the controlled rolling and controlled cooling experiment, the effect of finish rolling temperature and cooling rates on microstructure and mechanical properties of the non-quenched and tempered plastic mould steel is studied. The optimal controlled rolling and controlled cooling process parameters for the tested steel are determined and shown as follow: reheating temperature of1200～1250℃, begining temperature of910℃～930℃and finish temperature of about860℃respectively in finish rolling zone, air-cooling after rolling.(3) Cuting test results show that the cutting force of the non-quenched and tempered plastic mould steel is greater than P20, but at surface roughness and tool wear, the non-quenched and tempered plastic mould steel is better.(4) In all friction and wear cycle, the wear weight loss of the non-quenched and tempered plastic mould steel is more than the pre-hardened plastic mould steel P20. The friction and wear resistance of the non-quenched and tempered plastic mould steel is not better than the pre-hardened plastic mould steel P20.(5) Mirror polishing performance test results show that the surface roughness of the two plastic mould steel is more close to each other under the conditions of polishing fabrics TriDent and polishing paste WO.5. The value of their surface roughness is about0.084～0.086.