2205双相不锈钢锻造失效分析

Forging failure analysis on duplex stainless steel 2205

针对2205双相不锈钢在实际工业化生产中出现的锻造失效问题进行了研究。采用10 t EAF-AOD双联工艺冶炼2205双相不锈钢,浇注2支4.2 t钢锭。钢锭化学成分合格,表面质量良好,但在锻造开坯过程中,钢锭表面出现大量横向裂纹,导致锻件产品报废。利用金相显微镜、扫描电镜以及能谱分析仪等,对2205双相不锈钢在锻造过程中出现的裂纹缺陷进行金相组织、截面形貌及能谱分析。结果表明:2205双相不锈钢锻造失效主要原因是,锻前加热过程中,在850℃进行了时效处理,析出大量σ脆性相,导致钢的塑韧性急剧下降,受到变形力作用后表面严重开裂;热加工过程中,2205双相不锈钢在600~1000℃温度范围内应快速升温,不宜做时效处理,避免σ相析出,恶化钢的力学性能。

The forging failure problem of duplex stainless steel 2205 in actual industrial production was studied. Then,two 4. 2 tons steel ingots were poured by 10 t EAF-AOD duplex smelting process,and the chemical composition of ingot was qualified and the surface quality was good. But in the process of forging billet,the ingot surface appeared a lot of lateral cracks resulting in forging products scrapped.Therefore,the defects of duplex stainless steel 2205 during the forging process were studied by means of metallographic microscope,scanning electron microscope and energy dispersive spectrometer. The results show that the reason of forging failure of duplex stainless steel2205 was that the aging treatment was conducted at 850 ℃ during the heating process before forging,and a large amount of σ brittle phase were precipitated to result in the decrease of plastic toughness of steel and severe cracking of surface by deformation force. Furthermore,duplex stainless steel 2205 should be heated rapidly during the temperature range 600-1000 ℃ in hot working process,and the aging treatment should not be conducted to avoid the σ-phase precipitation worsening the mechanical properties of steel.