钢轨铝热焊砂型硬化工艺试验研究和失效分析  

Test research and failure analysis of rail thermite welding sand mold hardening process

作　　者：高松福 张健 任金雷 石孟雷 GAO Songfu;ZHANG Jian;REN Jinlei;SHI Menglei(Metals&Chemistry Research Institute,China Academy of Railway Sciences Corporation Limited,Beijing 100081,China)

机构地区：[1]中国铁道科学研究院集团有限公司金属及化学研究所,北京100081

出　　处：《中国铸造装备与技术》2021年第6期85-88,共4页China Foundry Machinery & Technology

基　　金：中国铁道科学研究院集团有限公司金化所基金项目(2052XC0203)。

摘　　要：采用吹CO_(2)硬化工艺和烘干硬化工艺制备钢轨铝热焊砂型,并测试砂型的破断压力。吹CO_(2)初期,由于水玻璃未完全反应,砂型破断压力比较低,吹气时间为140s时,砂型完全硬化,破断压力最高,当吹气时间进一步延长,过多的CO_(2)气体引起凝胶收缩出现裂纹,降低砂型的破断压力。烘干温度低于240℃时,水玻璃呈欠固化状态,砂型破断压力较低,当烘干温度超过260℃时,砂型破断压力下降。工业生产采用先吹CO_(2)进行砂型的表面硬化,然后再进行烘干硬化的砂型硬化工艺,生产和储运砂型的过程中,应当加强防湿防潮,避免砂型吸湿和表面“白霜”的产生。The CO_(2) blowing hardening process and drying hardening process have been used to prepare rail thermite welding sand mold,and the breaking pressure of the sand mold has been tested.In the initial stage of blowing CO_(2),due to the incomplete reaction of the water glass,the breaking pressure of the sand mold is relatively low.When the blowing time is 140s,the sand mold is completely hardened and the breaking pressure is the highest.When the blowing time is further extended,excessive CO_(2) gas causes gel shrinkage and cracks to reduce the breaking pressure of the sand mold.When the drying temperature is lower than 240℃,the water glass is under-cured,and the breaking pressure of the sand mold is lower.When the drying temperature exceeds 260℃,the breaking pressure of the sand mold decreases.Industrial production adopts the first blowing of CO_(2) to harden the surface of the sand mold,and then the sand hardening process of drying hardening.During the production,storage and transportation of sand mold,moisture prevention should be strengthened to avoid moisture absorption and surface"white frost".

关 键 词：钢轨铝热焊 砂型硬化 硬化工艺 

分 类 号：TG221[金属学及工艺—铸造]