Mooring chain steel and production process thereof, and mooring chain and production process thereof

Abstract

The mooring chain steel comprises the following components in percentage by mass: 0.18 to 0.32 percent of C, 1.95 to 2.60 percent of Mn, 0.15 to 0.50 percent of Si, 0.45 to 1.20 percent of Cr, 0.008 to 0.250 percent of Mo, 0.02 to 1.20 percent of Ni, less than or equal to 0.40 percent of Cu, less than or equal to 0.005 percent of S, 0.005 to 0.250 percent of Al, less than or equal to 0.35 percent of (V + Ti + Nb), less than or equal to 0.06 percent of (Sn + As + Sb), 0.0005 to 0.0040 percent of Ca, 0.010 to 0.025 percent of REM, 0.004 to 0.024 percent of N, less than or equal to 0.002 percent of O, less than or equal to 0.00015 percent of H and the balance of Fe and inevitable impurities. On the basis of improving the cost performance of R3, R4 and R4S grade mooring steel, by utilizing the river-bay effect of Mn influencing a continuous cooling curve of structural steel, namely similar to the influence rule of Mo, as the content of alloy Mn is increased to a certain amount, the continuous cooling curve of the steel begins to be bent, a component system for increasing cheap elements Mn and Al and reducing precious elements Mo and Ni is designed, and through trial production of the steel and a chain, the cost performance of the steel is improved. The effects of reducing the cost of the chain product and improving the obdurability of the chain product are achieved. The invention further relates to a mooring chain and a production process thereof.

Description

technical field [0001] The invention relates to the technical field of low-alloy steel, in particular to a mooring chain steel and its production process, as well as the mooring chain and its production process. Background technique [0002] Mooring chain steel finger diameter in Between the mooring chains with round steel. Because the mooring chain is immersed in seawater for a long time and the service environment is harsh, the mooring chain steel must have high strength, good toughness, seawater corrosion resistance, hydrogen evolution embrittlement resistance, fatigue resistance, wear resistance and other characteristics. In addition, in practical applications, it is usually bent into a ring, and the mooring chain steel needs to have good hot bending and welding properties. [0003] The target composition of R4 grade mooring chain steel with million-ton production is 0.22Mn1.5Cr0.8Ni0.8Mo0.45Nb0.03 provided by Shanghai No. 5 Iron and Steel Works (Liu Yongxin, Xu Yun, ...

AI Technical Summary

Problems solved by technology

As far as R3, R4, and R4S grade chains are concerned, there is no new type of high-strength and tough steel that can meet their cost-effective requirements.

For R3, R4, R4S grade chains with large diameters, the above steel grades cannot meet the requirements

[0005] In addition, cracks in mooring chain steel ingots and continuous casting slabs have always been a problem that affects production efficiency and cost (such as Zeng Haixia, Yang Jia, Analysis of cracks in R4 mooring chain steel, Special Steel Technology, 25 (2019) No2)), There has been no comprehensive solution for many years

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