Centrifugal casting process of high nitrogen austenitic stainless steel pipe under atmospheric pressure

Abstract

The invention relates to a technology for centrifugal casting of a high-nitrogen austenitic stainless steel pipe at normal pressure. The technology includes the steps of preparing ingredients, preparing a casting mold and a casting machine, conducting alloy smelting and pouring, carrying out shaping cleaning and heat treatment, recording and checking. The cast pipe is made of high-nitrogen austenitic stainless steel, the nitrogen content of the alloy melt or oversaturated alloy in the solidification process is larger than or equal to 0.65% N at the normal pressure, spontaneous gas can be generated in the normal-pressure casting process, and nitrogen bubbles overflow. Under the normal-pressure smelting condition, high-nitrogen-content austenitic stainless steel molten metal obtained by smelting meets the pouring temperature condition, and then enters in the pouring step rapidly in 90 seconds, and centrifugal casting of all the smelting molten metal is completed in three minutes. The auxiliary segregation effect of centrifugal force is utilized, and the overflowing nitrogen bubbles deviate from the quality specification portion of the cast pipe. By the adoption of the technology, the nitrogen content, the bubble positions and the bubble number can be controlled stably and effectively, and thus the surface and overall quality requirement can be met.

Description

technical field [0001] The invention belongs to the field of casting technology, and specifically relates to a process for centrifugally casting high-nitrogen austenitic stainless steel pipes under normal pressure. The purpose of stainless steel pipe. Background technique [0002] Nitrogen-alloyed high-nitrogen alloy steel, which has been widely valued in the world since the end of the 1980s, includes materials such as high-nitrogen stainless steel and high-nitrogen tool steel, especially high-nitrogen stainless steel. Due to its nickel saving and excellent performance, it has attracted the attention of various countries. It is even used as a strategic structural material. [0003] High-nitrogen stainless steel generally adopts pressure smelting technology. At present, the casting of products is limited by differential pressure casting technology, and products are cast under higher pressure, while there are only a few reports on normal pressure casting or ingot casting. Th...

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Problems solved by technology

[0005] In addition to the high pressure or differential pressure casting conditions used in the patented technology, the problems in the normal pressure test conditions in the past, either the nitrogen content did not meet the high nitrogen content requirements of the design, or the nitrogen overflow caused serious holes, and the qualified casting of normal pressure casting could not be realized. product