A thick-gauge acid-resistant x60ms hot-rolled coil and its manufacturing method

Abstract

The invention provides a thick acid-fastness X60MS hot-rolled coiled plate and a manufacturing method thereof. The steel plate comprises, by weight, 0.050%-0.070% of C, 0.15%-0.25% of Si, 1.35%-1.45% of Mn, 0.025%-0.045% of Nb, 0.008%-0.025% of Ti, 0.06%-0.10% of Mo, 0.08%-0.18% of Cr, 0.015%-0.045% of Als, no more than 0.015% of P, no more than 0.0015% of S, no more than 0.006% of N, and the balance Fe and inevitable impurities. The manufacturing method includes the steps of molten iron pretreatment, converter smelting, refining outside a converter, continuous casting, slab heating, rolling, cooling and coiling. A continuously cast slab is directly subjected to hot charging heating at the temperature of 500-850 DEG C, heated by a walking beam furnace to the temperature of 1160-1200 DEG C and then taken out of the furnace; and rolling is controlled in two stages, laminar cooling is conducted at the speed of 10-30 DEG C per second, and coiling is conducted at the temperature of 500-560 DEG C. The steel plate is simple and reasonable in alloy design, production cost is lowered, comprehensive performance of products is excellent, and especially the acid fastness and low-temperature breaking tenacity are good.

Description

technical field [0001] The invention belongs to the field of high-strength low-alloy steel, and in particular relates to a pipeline steel for oil and gas transportation and a method for manufacturing the hot-rolled coil. Background technique [0002] Corrosion is the main cause of pipeline failure accidents. Various statistics show that in the pipeline containing wet H 2 Under the action of S medium, oil and gas transmission pipelines are prone to corrosion. The pipeline is subjected to H 2 During S corrosion, uniform corrosion, pitting, hydrogen bubbling, hydrogen-induced step cracks, hydrogen embrittlement and stress corrosion cracking may occur, and various corrosion forms promote each other, eventually leading to pipe cracking and a large number of vicious accidents, resulting in huge economic loss and environmental pollution. in H 2 Among pipeline damages caused by S corrosion, hydrogen induced cracking (Hydrogen Induced Cracking, hereinafter referred to as HIC) and...

AI Technical Summary

Problems solved by technology

This invention adopts high-niobium design, which has high cost and does not use Cr, an economically beneficial element. The disadvantage is that the corrosion resistance of the product and the uniformity of the structure of thick-gauge products are slightly poor; in addition, the patent does not mention the SSCC resistance of the product.

Some of the above documents use more precious elements Nb, Ni, V, Cu, etc. in the alloy design, resulting in higher costs, and some use high-temperature heating, which consumes a lot of energy and increases manufacturing costs and pressure on the environment.

[0011] In some invention disclosures, the beneficial effects of Mo and Cr compound addition in thick gauge acid-resistant pipeline steel are not fully understood. Adding one of them or not adding it will result in slightly poor microstructure uniformity and corrosion resistance of the product. Other parts The literature only mentions the anti-HIC performance of the product, but does not consider the anti-SSCC performance

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