Patent TW-201529270-A (TW)
Title: Method for producing plastic mold made of martensitic chrome steel and plastic
Inventor: PERKO JOCHEN
IPC: C22C38/12
Filed: 2014-10-16
Abstract: The invention relates to a method for producing plastic mold made of steel iron. The plastic mold has high mechanical resistance, corrosive chemical resistance and polishing quality, wherein a steel block is made to have compositions (in wt%) as follows: C = 0.22 to 0.26, Si = 0.01 to 0.35, Mn = 0.15 to 0.60, P = max. 0.025, S = max. 0.003, Cr = 12.0 to 14.0, Mo = 0.10 to 0.18, Ni =0.35 to 0.50, V= 0.15 to 0.25, W = traces up to 0.20, Cu = traces up to 0.30, Co = traces up to 0.20, Ti = traces up to 0.02, Hf = traces up to 0.02, Zr = traces up to 0.02, Al = 0.002 to 0.02, Nb = traces up to 0.04, B = traces up to 0.001, N = 0.08 to 0.15, Ta = traces up to 0.04, and As = traces up to 0.005, with the conditions: Fe and impurities is = rest and with a PRE (N) value for the corrosion resistance of about 14.5 prepared to about 15.7 and higher 2.5-fold deformed primarily at a temperature of higher than 1050 ° C with a reduction ratio of what,Mn+Ni = 0.55 to 0.95, Mo+W/2 = 0.11 to 0.20, Ti+Hf+Zr = traces up to 0.05, V+Nb+Ta = 0.15 to 0.30, Nb+Ta = traces up to 0.04, Fe and impurities being the rest, and a PRE(N) value for the corrosion resistance being from more than 14.5 to approximately 15.7. Furthermore, the steel block is subjected to a primary deformation at a temperature of more than 1050 DEG C with a deformation degree of more than 2.5 times. Then, preferably after an intermediate cooling, at least one mold base is manufactured from the blank at a temperature of less than 1050 DEG C. A plastic mold is manufactured from the mold base preferably after a machining treatment, and the plastic mold or the mold base is austenitized and hardened at a cooling rate with a value [lambda] of less than 24. Then, at least two annealing treatments are carried out at a temperature in the range from 510 to 550 DEG C, resulting in that a hardness of the material is 48 to 52 HRC and a toughness thereof (measured on impact bending specimens) is at least 60 J. Then, if required, a final machining processing is performed. The present invention also relates to a plastic mold with high mechanical resistance, corrosive chemical resistance and polishing quality. The plastic mold is made of deformable alloy with the following compositions (in wt%): C = 0.22 to 0.26, Si = 0.01 to 0.35, Mn = 0.15 to 0.60, P = max. 0.025, S = max. 0.003, Cr = 12.0 to 14.0, Mo = 0.10 to 0.18, Ni =0.35 to 0.50, V= 0.15 to 0.25, W = traces up to 0.20, Cu = traces up to 0.30, Co = traces up to 0.20, Ti = traces up to 0.02, Hf = traces up to 0.02, Zr = traces up to 0.02, Al = 0.002 to 0.02, Nb = traces up to 0.04, B = traces up to 0.001, N = 0.08 to 0.15, Ta = traces up to 0.04, and As = traces up to 0.005, with the conditions: Mn+Ni = 0.55 to 0.95, Mo+W/2 = 0.11 to 0.20, Ti+Hf+Zr = traces up to 0.05, V+Nb+Ta = 0.15 to 0.30, Nb+Ta = traces up to 0.04, and Fe and impurities being the rest, wherein a hardness of the material is 48 to 52 HRC, a toughness measured on impact bending specimens is at least 60 J, an extensibility (breaking extension A by at least 5% when a cross-section is reduced to Z) is at least 10%, and PRE(N) value for the corrosion resistance is from more than 14.5 to approximately 15.7.