提高热作模具钢H13退火组织均匀性的措施  

MEASURES TO IMPROVE THE UNIFORMITY OF THE ANNEALING STRUCTURE OF HOT WORK DIE STEEL H13

作　　者：门志刚 Men Zhigang(HBIS Group Zhangxuan Technology Company,Xuanhua 075100,Hebei)

机构地区：[1]河钢集团张宣科技,河北宣化075100

出　　处：《河北冶金》2023年第9期63-66,共4页Hebei Metallurgy

摘　　要：某特钢厂在高端热作模具钢H13生产过程中,在对其退火组织进行检测时,发现个别批次未能达到北美压铸协会NADCA#207-2003的要求,评级为AS10~AS13不合格级别,金相组织在显微镜下呈现不同程度网状和链状碳化物分布,组织均匀性也较差。较差组织易造成模具在使用过程中早期开裂,同时降低冲击韧性导致使用寿命缩短。为解决组织差问题,分析了退火组织异常的原因,并进行了针对性工艺优化。通过控制电渣冶炼熔速降低铸锭合金偏析,保证夹杂物充分上浮析出,提升铸锭纯净度;优化高温均质化均热段温度和时间,促进偏析元素快速溶解并重新均匀分布,改善带状偏析;超细化热处理工艺细化晶粒尺寸和实现均匀分布,提升晶界结合强度;控制锻造变形方式和终锻温度,对铸态组织进行破碎,实现细化晶粒,提高材料致密性;优化热处理冷却方式,进一步降低二次碳化物析出量及成链状网状概率等一系列措施,退火组织碳化物尺寸、分布和均匀性得到明显改善,合格率达到99%以上。In the production process of high-end hot work die steel H13,when testing the annealing structure,a special steel mill found that some batches failed to meet the requirements of NADCA#207-2003 of the North American Die Casting Association,and the rating was AS10~AS13 unqualified grade,and the metallographic structure showed different degrees of network and chain carbide distribution under the microscope,and the tissue uniformity was also poor.Poor structure can easily cause early cracking of the mold during use and reduce the impact toughness and shorten the service life.To solve the problem of poor tissue,the causes of abnormal annealing tissue were analyzed,and targeted process optimization was carried out.By controlling the melting rate of electroslag smelting,the segregation of ingot alloy is reduced,so as to ensure that the inclusions fully float out and improve the purity of ingots;optimize the temperature and time of the soaking heat section of high temperature homogenization,promote the rapid dissolution and redistribution of segregated elements,and improve band segregation;the ultra-fine heat treatment process refines the grain size and achieves uniform distribution to improve the grain boundary bonding strength;control the forging deformation mode and final forging temperature,crush the casting structure,realize the refinement of grains,and improve the compactness of the material;a series of measures such as optimizing the heat treatment cooling method,further reducing the amount of secondary carbide precipitation and the probability of forming a chain network have significantly improved the size,distribution and uniformity of carbide in the annealed tissue,and the qualification rate has reached more than 99%.

关 键 词：热作模具钢 退火组织 电渣冶炼 熔速 高温均质化 锻造变形 风冷 

分 类 号：TG142.1[一般工业技术—材料科学与工程]