Welding wire suitable for welding low-strength H2S-corrosion-resistant pipeline steel in submerged arc mode

Abstract

The invention discloses a welding wire suitable for welding low-strength H2S-corrosion-resistant pipeline steel in a submerged arc mode. The welding wire is composed of, by weight, 0.03-0.05% of C, 0.5-0.8% of Mn, 0.1-0.22% of Si, smaller than or equal to 0.005% of P, smaller than or equal to 0.004% of S, 0.1-0.2% of Cu, 0.06-0.15% of Ti and 0.005-0.012% of B and is further composed of, by weight, one or two of 0.2-0.5% of Ni and 0.1-0.2% of Mo and the balance Fe, wherein the sum of C%, Si% / 30, Mn% / 20, Cu% / 20, Mo% / 15 and Ni% / 60 is smaller than or equal to 0.15. The welding wire is mainly developed for welding the low-strength H2S-corrosion-resistant pipeline steel in the submerged arc mode, and the low strength of 360 Mpa to 420 Mpa corresponds to the steel grade of X52MS to X60MS of the acid-resistant pipeline steel; according to the welding wire, on the basis of adding a small amount of Ni and Mo, the contents of impurities of P and S are controlled as mush as possible, it is ensured that a welding joint meets the mechanical properties of an H2S-corrosion-resistant welding pipe with low strength of 360 Mpa to 420 Mpa, and the quite excellent H2S corrosion resistance is achieved as well.

Description

Technical field: [0001] The invention relates to a welding wire, in particular to a welding wire suitable for low-strength (360Mpa-420Mpa) H-resistant 2 The invention relates to a welding wire for submerged arc welding of S corrosion pipeline steel, which belongs to the field of welding materials. Background technique: [0002] h 2 S is one of the most corrosive and harmful media in oil and natural gas, which seriously affects the service life of oil and gas pipelines, among which hydrogen-induced cracking (HIC) and sulfide stress cracking (SSCC) are H 2 The main form of S acid corrosion restricts the safe service of oil and gas pipelines. [0003] Many foreign pipelines directly transport acidic oil and gas, so there is a large demand for acid-resistant pipes. Most oil and gas fields in my country contain hydrogen sulfide, and some gathering and transportation pipelines are in an acidic corrosion environment, so it is necessary to research and develop acid-resistant pipe...

AI Technical Summary

Problems solved by technology

Chinese patent CN1273897 belongs to the welding wire above X70 steel grade, the Mn content in the welding wire is relatively high, the Mn content is designed to be above 1.2%, and the yield strength reaches 520MPa. It belongs to high-strength acid-resistant pipeline steel welding wire, but there is no HIC and SSCC test data. Corrosion resistance unknown

Although the Chinese patent CN103056555 is applicable to X52-X65 steel grade acid-resistant pipes, the Mn content in the welding wire is 0.8%-1.2%. Due to the high Mn content, the weld seam is easy to segregate and the local hardness of the weld seam is easy to increase, and the weld seam hardness has a certain Fluctuation, resulting in unstable SSCC stress corrosion resistance of welds and limited stress corrosion resistance

Images