Economical non-quenched and non-tempered micro-alloyed plastic die steel plate and making method thereof

Abstract

The invention discloses an economical non-quenched and non-tempered micro-alloyed plastic die steel plate and a making method thereof. The economical non-quenched and non-tempered micro-alloyed plastic die steel plate comprises 0.32-0.40wt% of C, 0.20-0.50wt% of Si, 1.00-1.50wt% of Mn, 1.20-1.70wt% of Cr, 0.20wt% or less of Mo, 0.0025wt% or less of B, 0.03wt% or less of Ti, 0.03wt% or less of Nb, and the balance Fe. The making method comprises the following steps: carrying out converter smelting, LF+RH refining and continuous slab casting; heating the obtained slab at 1200-1230DEG C, carrying out precision rolling at 900-950DEG C, and carrying out finishing rolling at 870-920DEG C; carrying out controlled cooling after the steel plate rolling; and tempering the steel plate obtained after the controlled rolling and controlled cooling at 550-600DEG C to obtain the finished pre-hardened plastic die steel plate having a bainite structure. The yield strength, the normal temperature impact toughness and the cross section hardness of the steel plate are above 800MPa, above 20J and 310-350HB respectively. The making method is suitable for the production of pre-hardened plastic die steel plates with the specification of below 120mm from 320mm continuous casting blanks.

Description

technical field [0001] The invention relates to a plastic mold steel plate and a manufacturing method thereof, in particular to an economical non-tempered microalloyed plastic mold steel plate and a manufacturing method thereof. Background technique [0002] With the rapid development of my country's plastics industry, the market demand for plastic mold steel is increasing. In order to improve the service life of the mold, the processing accuracy of the mold and the quality of plastic products, the market has higher and higher requirements for the quality of mold steel. The traditional plastic mold steel means that the hot-processed steel plate is firstly quenched and tempered to reach the hardness range required by the plastic mold steel, and then mechanically processed, so as to avoid mold deformation and cracks caused by heat treatment. Although plastic mold steel has the above advantages, it also has the characteristics of high quenching crack sensitivity, high productio...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to overcome the two major disadvantages of non-quenched and tempered plastic mold steel plate alloy cost and manufacturing cost, and uneven microstructure and section hardness, and provide an economical non-quenched and tempered micro-alloyed pre-hardened plastic Die steel plate and manufacturing method thereof

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