热处理对锻造铅黄铜组织和性能的影响

研究了退火温度对锻造铅黄铜组织和力学性能的影响.对铸造成型的商用铅黄铜进行720℃、60%变形量的锻造镦粗加工后,采用500~700℃不同温度的热处理工艺处理.结果表明：铅黄铜的铸态组织为粗大的树枝晶,锻造后的晶粒被拉长,与铸态的硬度值相比,锻造后的硬度明显增加,产生明显的加工硬化现象;锻造铅黄铜经过热处理后,细长的晶粒明显变短,随着退火温度的升高,晶粒逐渐细小、均匀化,并且发生再结晶,拉长的晶粒逐渐变为等轴晶.620℃、640℃退火后,铅黄铜的组织基本转变为细小、均匀的等轴晶,退火温度超过640℃时,随着温度的升高,晶粒长大.不同温度退火处理后,随着退火温度的升高,硬度逐渐降低,620℃退火后硬度趋于稳定,加工硬化消除.铅黄铜经720℃、60%变形锻造后,合适的退火温度为620~640℃.

Influence of Heat Treatment on Microstructure and Properties of Forging Lead Brass Alloy

Effect of forging and heat treatment on microstructure and property of lead brass is studied. Heat treatment in 500-700 ℃ temperature is used for casting lead brass after forging in 720 ℃, 60% deformation. The results show that, the cast microstructure is coarse dendrite. The grains are elongated after forging. Compared with the casting, the hardness is increased and work hardening is produced significantly after forging. Slender grains are shorter after heat treatment and grains change short with the increase of annealing temperature, and starte the recrystallization. When the temperature reaches from 620 ℃ to 640 ℃, the equiaxcrystal almost comes into being short and homogeneous. When the temperature is more than 640 ℃ ,the grain increases rapidly with the increase of temperature After heat treatment, hardness decreases with the increase of annealing temperature. After forging 60% deformation, the suitable annealing temperature of lead brass is from 620 ℃ to 640 ℃.