铣刨齿钢体冷挤压成形工艺与模具设计分析

Analysis of Cold Extrusion Forming Process and Die Design for Steel Body of Milling Teeth

针对铣刨齿钢体需要多工序成形的特点,从工艺方案制定、冷挤压工艺参数选择、模具结构设计等方面对铣刨齿钢体成形质量的影响因素进行分析,主要对铣刨齿钢体进行正挤压和镦法兰两工序成形模具结构分析,研究了退火热处理工艺对35MnB钢挤压工艺性能的影响。试验结果表明,当35MnB钢组织球化等级为5、6级时,可以进行连续冷挤压成形,即正挤压后不需要中间热处理即可进行镦法兰工序成形;当球化组织等级为3、4级时,正挤压后,需要增加中间退火工序,才可以进行镦法兰工序,否则会引起法兰端面开裂现象。本文工艺在两挤压工序之间不需要进行热处理工序即可保持挤压件主体的金属流线完整。

Aimed at the characteristics of the steel body of the road milling teeth which requires multi-process forming,the influence factors of the forming quality of the steel body of the road milling from the aspects of the formulation of the process plan,the selection of the cold extrusion process parameters and the design of the die structure were analyzed,and the structure of the forming dies of the forward extrusion process and flange-upsetting process was mainly analyzed.The influence of the heat treatment process of annealing on the extrusion process performance of 35MnB steel was studied.The test results reveal that continuous cold extrusion can be performed when the metallographic structure spheroidization level of the 35MnB steel is 5,6,that is,after the forward extrusion,the flange-upsetting process can be performed without the intermediate heat treatment.When the spheroidized structure level is 3,4,after the forward extrusion,the intermediate annealing process needs to be added to perform the flange-upsetting process,and otherwise the flange end face may be cracked.This process can maintain the completeness of the metal streamline of the main body of the extrusion workpiece without the heat treatment between the two extrusion processes.