High intensity, corrosion resistant and high ductility steel for mooring chain and production process thereof

Abstract

The invention discloses a high-strength corrosion resistant high-tenacity steel which is used for mooring chain and a production process hereof; the chemical components (wt percent) are: 0.18 percent to 0.25 percent of C, 0.10 percent to 0.35 percent of Si, 1.40 percent to 1.80 percent of Mn, 0.80 percent to 1.40 percent of Cr, 0.60 percent to 1.20 percent of Ni, 0.40 percent to 0.70 percent of Mo, 0.02 percent to 0.06 percent of Nb, 0.02 percent to 0.06 percent of Al, S which is less than or equal to 0.010 percent, P which is less than or equal to 0.020 percent, B which is less than or equal to 0.005 percent, Cu which is less than or equal to 0.20 percent, Sb which is less than or equal to 0.010 percent, Sn which is less than or equal to 0.03 percent, As is less than or equal to 0.04 percent, [O] which is less than or equal to 0.0018 percent, [N] which is less than or equal to 0.0060 percent and the rest is Fe. The invention avoid producing martensite tissue with optimized design of components and in this way the material tissue can not be converted to produce central crack in a long-term placement under the situation that the parent metal does not adopt annealing process; at the same time the precious metal Ni is saved. The invention adopts RH / VD for desaeration and removing impurities and in this way, the purity of the steel can be obviously increased; the invention adopts converter for melting which reduces the energy consumption and saves cost.

Description

Technical field: [0001] The invention relates to alloy steel in the iron and steel industry, in particular to the design and production process of high-strength, corrosion-resistant and high-toughness steel for mooring chains. Background technique: [0002] With the development of modern industry, the development of marine resources is getting deeper and deeper. In particular, marine facilities such as deep-sea oil production, marine exploration, and national defense construction require the use of a large number of mooring chains. load, all put forward strict requirements on the overall performance of the mooring chain, not only require high strength and good toughness of the material, but also require the material to have good seawater corrosion resistance, fatigue resistance, wear resistance, good welding performance and low temperature of the weld joint Impact toughness. The diameter of the bars used to manufacture mooring chains is generally φ70mm-φ160mm, of which mor...

AI Technical Summary

Problems solved by technology

However, due to the overall high setting of the alloy composition, the structure of the material is semi-martensitic, and the material must be annealed before delivery, otherwise the material will undergo martensitic transformation during placement, resulting in structural stress, resulting in material Internal cracks appear, once internal cracks occur, the material will be scrapped as a whole, and the Ni content in the composition is high, which not only increases the cost, but also causes a waste of resources