Oil-gas transportation large-scale high-pressure pipe fittings steel as well as pipes, pipe fittings and welding materials produced thereby

Abstract

The invention relates to steel used for oil and gas transportation large high pressure pipe fittings and steel pipes, pipe fittings and welding materials made of the steel. The invention is developed for solving the problems of the low grade, high carbon content, poor welding property, etc., of the present fitting used steel. The compositions of the steel are less than or equal to 0.12 percent of C, less than or equal to 0.35 percent of Si, less than or equal to 1.60 percent of Mn, less than or equal to 0.030 percent of P, less than or equal to 0.015 percent of S, less than or equal to 0.50 percent of Ni, less than or equal to 0.30 percent of Cr, less than or equal to 0.30 percent of Cu, less than or equal to 0.25 percent of Mo, less than or equal to 0.05 percent of Nb, less than or equal to 0.09 percent of V, less than or equal to 0.05 percent of Ti and less than or equal to 0.060 percent of Al, and the rest is Fe. When using the steel of the invention for producing the oil and gas transportation high pressure steel pipes and the welding materials, the fitting heat treatment quenching heating temperature is 900-980 DEG C. The quenching heating time is the wall thickness of the fittings in millimeter multiplied by 2-3m/mm; the tempering heating temperature is 600-700 DEG C; the tempering heating time is the wall thickness of the pipes in millimeter multiplied by 3-6m/mm. the oil and gas transportation high pressure pipe fittings of the invention can satisfy the production demands of high pressure steel pipes and fittings for X80 grade pipeline.

Description

[technical field] [0001] The invention relates to a steel for pipe fittings of high-pressure pipelines for oil and gas transportation, and high-pressure steel pipes, pipe fittings and welding materials produced therefrom. [Background technique] [0002] The existing steel for pipe fittings has a low steel grade, high carbon content, poor weldability, and low impact toughness, which cannot meet the needs of steel pipes and pipe fittings for high-grade pipelines. [Content of the invention] [0003] The object of the present invention is to provide a steel for large-scale high-pressure pipe fittings for oil and gas transportation and the steel pipes, pipe fittings and welding materials made therefrom. [0004] The purpose of the present invention is achieved like this: [0005] 1. Develop a steel for large-scale high-pressure pipe fittings for oil and gas transmission. The steel grade is high, the content of carbon, sulfur and phosphorus is low, and it has good mechanical p...

AI Technical Summary

Problems solved by technology

[0002] The steel grade of existing pipe fittings is low, the carbon content of steel is high, the welding performance is poor, and the impact toughness is low, which cannot meet the needs of steel pipes and pipe fittings for high steel grade pipelines

Images