基于金相分析技术的煤矿火灾事故调查试验研究

通过对矿井火灾现场特性的分析,根据金属材料的特点,提出利用金相鉴定技术进行矿井火灾事故调查的新方法,试验测定得出高温作用下40号钢和铸铁的金相组织和硬度的动态变化规律。试验结果表明,不同加热温度条件下,40号钢冷却后具有不同的金相组织,其硬度随受热温度的升高迅速下降;在相同加热温度不同受热时间条件下,40号钢的金相组织与硬度变化不明显。铸铁的硬度随加热时间的增加呈下降趋势,其金相组织也有较明显的区别。根据矿井火灾后降温较为缓慢的特点,提出灰口铸铁与白口铸铁相互转变的方向性。因此,矿井火灾事故调查可以对受到火灾破坏的金属构件的金相组织的观察和硬度测定,来"反推"出该部位在火灾时曾受过的最高温度以及持续时间,从而可推断火灾的蔓延情况,为认定起火原因和起火位置提供技术支持。

Experimental Research of Fire Accident Investigation in Coalmine Based on Metallographic Analysis Technique

By analyzing the sites features of mine fire and according to the specialty of metal material,a new method of mine fire accident investigation through using metallographic identification technique was proposed.Dynamic change disciplinarian of metallographic phrase and hardness of the No.40 steel and cast-iron were gained under high-temperature by experiment.The results show that,under different heating temperature,the cooled No.40 steel appears different metallographic phrase and its hardness declines with the heating temperature increasing;while under the same heating temperature and different holding time,the metallographic phrase and hardness of the cooled No.40 steel almost keep the same.However,the hardness of cast-iron declines with the heating holding time increasing,and its metallographic phrase obviously appears much difference.From those results,it can be found out that there is a direction of mutual transformation between ash-cast and white-cast.Therefore,through observing the metallographic phrase and measuring the hardness of the steel suffering fire during fire accident,the accident investigation expert can anti-infer the maximum temperature suffered and the holding time of the fire-suffering part of the steel,and thus infer the spreading situation of mine fire,which provides technical supports for determining the causes and initial position of mine fire.