Japanese cold work die steel developments - from the SKD1 transfer to SKD11

    High-carbon high-chromium cold work tool steel in World War I as the generation of high-speed tool steel steel-ups, post-war understanding of this excellent wear resistance and heat treatment of steel deformation is small, as the representative of the world are now cold-working die steel is widely used.
    High-carbon high chromium die steel have 2% C-13% Cr Department of SKD1 and 1.5% C-13% Cr lines SKDl1, former European type, which the U.S. type. Japan since before World War II, most of the use of tool steel imported from Europe, which is famous Bai Lu (Bohler) K Steel Special Steel Company, the equivalent of SKD1. 1947 years (Showa 22 years) of the Japanese Industrial Standards JES provides that SKD1 and SKD2 (the equivalent of special steel XW5) two kinds of cold work die steel. Shown in Table 1.
Table 1 JES standard cold die steel, the average chemical composition (mass fraction) /% (1947 -)

Grade	C	Si	Mn	Ni	Cr	W	P	S
SKD1	2.25	<0.50	<0.60	<0.50	13.50	-	<0.030	<0.030
SKD2	2.00	<0.50	<0.60	<0.50	13.50	3.00	<0.030	<0.030
	HC-Japanese cold work die steel developments-03

    SKD2 add 3.0% W, but also increased wear resistance. But SKD2 forging and other thermal processing of very poor, difficult to machine processing, so limited to the drawing die or block its rules to use. JIS revision of 1983, with almost no production performance and abolished.
    Now, the most widely used cold work tool steel JIS 1956 standardized SKD11. SKD1 by 2% C-13% Cr such a high carbon and high chromium, so the block contains a lot of hard chromium and a carbide coarse M7C3, (Fe, Cr) 7C3, high wear resistance but low toughness . In addition, due to poor hardenability carbon (eutectoid carbon content of hardenability when the largest component), not oil quenching hardness is difficult to get enough of their shortcomings.
    In the U.S., there is no D3 (equivalent to SKD1) shortcomings of the D2 steel steel (equivalent to SKD11) generalizable.
    D2 steel carbon content of 1.5% is relatively low, in order to increase the hardenability added 0.8% Mo, wear compensation added 0.6% V. As a result, a massive carbon reduction, a slight decrease in wear resistance, processability, toughness and hardenability increases, as easy to use steel.
    Showa 30's in Japan, cold mold material is transferred from the SKD1 to SKD11 period. But before the war began special steel K Hitachi's reputation or brand name of the CRD. This shift is not smooth. Quenching temperature of 950 ℃ with SKD1 contrast, SKD11 quenching temperature should be 1025 ℃ high temperature, heat treatment furnace at the time the old-fashioned to avoid such high quenching temperature is also a factor. SKD11 as thread forming roll or roll forming applications for high performance. In addition, as SKD11 understand the various features, established SKD11 as stamping material status. Daido Steel in Japan with the development of cold steel including tool steel: DC11, DC1, DC2, DC12, DC3, DC5, DC8, DC53, DCX, DCLT, DCMX, YK30, GOA, etc.; the development of the Japanese Hitachi steel, tool steel cold species include: SLD, ARK1, SLD8, SLD10, CRD, YCS3, SGT, ACD37, HMD1, HMD5, HPM1 etc.; Japan, Sanyo Special Steel development tool steel cold steel include: QC1, QC11, QCM7, QCM8, QK3M , QKS3, QF3, QHZ and so on.
SKD12 is to AISI A2 Japan JIS standard in 1% C-5% Cr steel add molybdenum, vanadium air hardening steel. In Japan, SKD12 steel and low alloy tool steel SKD11 between SKS3, its features are two steel in the middle, so there is no how the application.

More information
Please direct Hong Chao(DongGuan) Mould & Technology Co., Ltd. service contact (hotline 0769 -82621066 / 82621088, the National Service Hotline :400-699-1286) for more on Japanese cold work die steel developments and high-quality mould steel (Japan Daido tool steel DC53_NAK80 Sweden ASSAB mould steel S136_VIKING, Germany Groditz mould steel, Japan Fuji high-speed steel, Japan's Hitachi mould steel, etc.) the selection, application, heat treatment and inventory and other related information.
Source: Hong Chao(DongGuan) Mould & Technology Co., Ltd. Technology Center
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