US 11,946,120 B2
Method for controlling amount of silicon added to ductile cast iron, method for casting ductile cast iron, and cast product
Jianchen Cong, Weihai (CN); Shibo Shao, Weihai (CN); Haiming Yu, Weihai (CN); Xuezhong Dai, Weihai (CN); Peixiang Ni, Weihai (CN); Meizhen Feng, Weihai (CN); Shijie Lv, Weihai (CN); and Hongri Cong, Weihai (CN)
Assigned to TIANRUN INDUSTRY TECHNOLOGY CO., LTD., Shandong (CN); and SHANDONG UNIVERSITY OF TECHNOLOGY, Shandong (CN)
Appl. No. 17/642,572
Filed by TIANRUN INDUSTRY TECHNOLOGY CO., LTD., Weihai (CN); and SHANDONG UNIVERSITY OF TECHNOLOGY, Zibo (CN)
PCT Filed Aug. 28, 2020, PCT No. PCT/CN2020/112243
§ 371(c)(1), (2) Date Mar. 11, 2022,
PCT Pub. No. WO2021/057386, PCT Pub. Date Apr. 1, 2021.
Claims priority of application No. 201910916689.5 (CN), filed on Sep. 26, 2019.
Prior Publication US 2022/0325390 A1, Oct. 13, 2022
Int. Cl. C22C 37/10 (2006.01); C21C 1/10 (2006.01); C21D 1/28 (2006.01); C21D 1/32 (2006.01); C21D 5/14 (2006.01); C22C 37/04 (2006.01)
CPC C22C 37/10 (2013.01) [C21C 1/10 (2013.01); C21D 1/28 (2013.01); C21D 1/32 (2013.01); C21D 5/14 (2013.01); C22C 37/04 (2013.01); C21D 2211/005 (2013.01); C21D 2211/009 (2013.01)] 11 Claims
 
1. A method for controlling an amount of silicon added to ductile cast iron, comprising:
smelting ductile cast iron using scrap steel as a raw material, wherein after the scrap steel is melted into molten iron, a copper alloy is first added so that the molten iron has a copper equivalent of 0.8% to 1.0%, and then ferrosilicon is added so that a content of silicon added to the molten iron satisfies a following formula (I):
Siadded=1.3CuE+10P+4S−Sioriginal  formula (I),
in formula (I), Siadded is the content of silicon added to the molten iron, and CuE is the copper equivalent in the molten iron; and P, S, and Sioriginal are a phosphorus content, a sulfur content, and a silicon content in the molten iron before the ferrosilicon is added, respectively;
wherein the copper equivalent is controlled by formula (II):
CuE=[WCu]newly added+[(WMn−0.45%)/2.5+1.1WCr+(WMo−0.15%)/2+0.1WNi+12WSn+WCu+4Wv]original  formula (II),
in formula (II), CuE is the copper equivalent, [WCu]newly added is a content of copper added to the molten iron, and WMn, WCr, WMo, WNi, WSn, WCu, and Wv are a manganese content, a chromium content, a molybdenum content, a nickel content, a tin content, a copper content, and a vanadium content originally present in the molten iron, respectively,
wherein a mixture of microcrystalline graphite powder and silicon carbide crystal is added in duration that scrap steel is being melted into the molten iron, and
wherein the mixture of microcrystalline graphite powder and silicon carbide crystal is added in an amount of 4% to 6% of the molten iron in weight.