连续退火工艺对含B搪瓷用钢组织性能的影响

INFLUENCE OF CONTINUOUS ANNEALING PROCESS ON MICROSTRUCTURE AND PROPERTIES OF BORON CONTAINING ENAMEL STEEL

研究了连续退火工艺对含B搪瓷用钢微观组织特征、力学性能和H渗透行为的影响.材料在实验室条件下加工生产,采用连续退火模拟机进行连续退火工艺模拟.研究发现,采用高温短时间保温的退火板晶粒及晶粒内渗碳体颗粒尺寸均相对较大,珠光体独立存在;而采用相对低温长时间保温的退火板晶粒尺寸相对较小,晶粒内渗碳体颗粒细小弥散,珠光体呈链状分布.实验钢板在选取的退火工艺范围内强度和加工硬化指数n值变化不大,断后伸长率和塑性应变比r值均较高.高温短时间保温更有益于钢板获得较强的γ织构,有利于冲压成形.实验钢组织中存在一定规模的MnS夹杂、渗碳体颗粒和珠光体,其与基体间的界面可作为有效H陷阱,因此H在钢中的扩散系数很低.相对低温长时间保温得到的相对细晶组织+链状退化珠光体和细小弥散的渗碳体颗粒更加有助于降低H在钢中的扩散速率,提高搪瓷用钢板的抗鳞爆性能.

Enamel product has been developed and more widely used with the development of metallurgical technology and equipments. Its quality is closely related to its metal substrate whicii needs both nice mechanical properties to meet ability to meet sufficient fish-scale resistance deep drawing request and excellent hydrogen trapping In order to obtain those properties, the influence of continuous annealing process on microstructural characteristics, mechanical properties and hydrogen permeation behavior of boron containing enamel steel was investigated. Tim material was produced and processed in lab and the continuous annealing process was performed using a continuous annealing silmflator. It was found that in anneaied sheet using high temperature and short time soaking, the sizes of both ferrite grains and cemetite particles within matrix are relatively larger, pearlite exist independently; while using relatively low temperature and long time soaking, the size of ferrite grains is smaller, cemetite particles within matrix are fine and dispersed, pearlite exist as chains. Within the scope of the annealing process adopted, strengths and work hardening exponent n- values of annealed sheets do not differ much, elongations and plastic anisotropy ratio r-values are both high. High temperature and short time soaking is more advantageous to steel sheet obtaining strong γ fiber texture, which benefits the deep drawing of sheet. There are certain scale of MnS inclusions, pearlite