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一、钢丝束松弛试验大量用于预应力铁路梁的φ5mm高强度钢丝,其极限强度、条件流限、延伸率及冷弯等技术指标一般均能符合要求,但各钢厂均缺少提供有关钢丝松弛的资料。 1966年铁道科学研究院曾对天津钢厂生产的单根钢丝进行了松弛试验,ò_a=0.7ò_p在1080小时时,其损失值为4.25％,在预应力梁设计时所采用的5％之内,满足要求。近年来天津钢厂改变生产工艺,由原先9mm圆钢冷
First, the steel wire bundle relaxation test A large number of φ5mm high-strength steel wire used for prestressed railway beams, the ultimate strength, conditions of flow limits, elongation and cold bend and other technical indicators generally meet the requirements, but the steel mills are lack of provision of the wire Relaxed information. In 1966, the Institute of Railway Research conducted a relaxation test on a single steel wire produced by a Tianjin steel mill. The loss at that time was 4.25% at 1080 hours and within 5% of the prestressed beam design ,fulfil requirements. Tianjin steel mills in recent years to change the production process, from the original 9mm cold bar