Steel for induction heating syphon for oil gas transportation and method for producing hot rolled slab thereof

Abstract

The invention provides steel for an economic-type induction heating syphon for oil gas transportation and a method for producing a hot rolled slab thereof. The steel comprises the following compositions: 0.06 to 0.11 percent of C, 0.15 to 0.30 percent of Si, 1.50 to 1.80 percent of Mn, 0.03 to 0.06 percent of Nb, 0.010 to 0.025 percent of Ti, 0.010 to 0.045 percent of Als and the balance of iron and inevitable impurities. The production method comprises smelting, external refining, continuous casting, and rolling; in the rolling process, the heating temperature of a continuous casting blank is between 1,100 and 1,150 DEG C; the rough rolling temperature is between 960 and 1,000 DEG C; the deformation of each pass is over 15 percent; the finish rolling temperature is between 780 and 920 DEG C; the accumulated deformation is 55 to 75 percent; a cooling speed after rolling is between 15 and 35 DEG C / s; and the final cooling temperature is between 400 and 550 DEG C and then air cooling is carried out. Under the condition of not increasing production procedure, the method reduces the production cost by reducing the content of a noble alloy element and optimizing a production process, ensures that a steel plate reaches the steel standard of the X80-level induction heating syphon, and also ensures the performance stability after a material is subjected to heat treatment.

Description

technical field [0001] The invention belongs to the technical field of low-carbon micro-alloy steel, and in particular relates to steel for induction heating elbows used in manufacturing high-pressure and large-diameter oil and gas pipelines. Background technique [0002] Induction heated pipe bends, as structural parts with relatively harsh loads in pipelines, are frequent parts of pipeline accidents. The quality of pipe bends is an important factor affecting the safe operation of pipelines. This requires that the hot-rolled steel plates used to manufacture pipe bends have good Comprehensive performance. [0003] At present, the highest grade of bend pipe widely used in domestic projects is X70 grade (yield strength 490MPa grade). The steel for bending pipes that has been used is usually designed with low carbon components, such as the Japanese patent for bending pipes with publication number JP2002-129288, its composition is (weight percentage) C: 0.03% or less, Si: 0.30%...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problems of high production cost and unstable performance after heat treatment in the prior art, and provide an economical X80 grade high toughness induction heating bending pipe steel

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