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本文研究了GH30合金管内壁裂纹形成的机理,考察了管坯加热温度、轧辊转速、顶头预热温度和轧辊倾角等工艺因素对荒管内壁裂纹的影响,从而给在生产实践中证明为消除裂纹的可靠工艺措施提供了进一步论证。 研究结果表明:由于管坯加热温度偏高,穿孔中顶头同金属间形成一种粘结摩擦,使荒管内壁表层金属的瞬时温升很高,导致晶界弱化和“失塑”,在变形过程中各种应力的综合作用下,使内壁金属极易破坏而形成沿晶发展的粘结摩擦热致裂纹。
In this paper, the mechanism of crack formation in the inner wall of GH30 alloy tube was studied. The effects of the factors such as the heating temperature of the tube, the rotating speed of the roll, the head preheating temperature and the dip angle of the roll on the inner wall cracks of the bare tube were investigated. The reliable process measures provide further proof. The results show that due to the high heating temperature of the billet, the bond between the head and the metal in the perforation forms a bond friction, so that the instantaneous temperature rise of the surface metal in the waste wall is very high, which leads to the grain boundary weakening and “plastic loss” Under the combined action of various stresses in the process, the metal in the inner wall is easily destroyed and the interfacial friction thermal cracking caused by the crystal growth is formed.