摘要
本文通过金相法对比研究了真空感应熔炼气雾化法(VIGA)与等离子旋转电极法(PREP)制备不锈钢粉末的内部孔洞特征。结果表明:两种制粉工艺制备的粉末均表现出粉末粒径越大,空心粉数量越多的特点,粉末中孔洞形状基本呈球形。两种制粉过程中,粉末的内部孔洞形成机理不同:VIGA法制粉工艺中,液滴雾化过程中伴随着快速冷却,二次破碎时袋状破碎进行不完全,气体留在液膜中,凝固后形成大量的空心粉。PREP法制粉过程中,气体压力较低(0.1 MPa),极少量气体在棒料高速旋转形成的负压作用下进入端面熔化液膜的中心位置,气体随液膜移动,包含气体的液膜在离心力作用下形成液滴,凝固后形成含有孔洞的空心粉,该工艺下含有孔洞的空心粉数量极少。
In this paper,a comparative research on the characteristics of porosity in stainless steel powders manufactured by vacuum induction-melting gas atomization(VIGA)and plasma rotating electrode process(PREP)were conducted via metallographic examination.The results show that the number of hollow powders increases with the increment of particle size in both powders.Meanwhile,the morphology of porosities primarily exhibites a spherical shape.The forming mechanisms of porosity in VIGAed and PREPed powders are quite different in essence.The atomization is accompanied by the rapid cooling of droplets during VIGA process.The incomplete bag breakup during secondary breakup stage causes gas preservation inside the liquid film.Considerable hollow powders form after droplets solidification due to the gas preservation.While in the case of PREP with low pressure of gas(0.1 MPa),a minute amount of gas enters into the core of melted end face under the negative pressure generated from high-speed rotation of the metal bar.The invaded gas would further move along with the liquid film.The gas-containing liquid film forms droplets under the control of centrifugal force.Consequently,a small amount of hollow powders with porosity are produced after solidification during PREP.
作者
胡家齐
王长军
魏来
杨哲
梁剑雄
董瀚
HU Jiaqi;WANG Changjun;WEI Lai;YANGZhe;LIANG Jianxiong;DONG Han(Iron and Steel Research Institute,Beijing 100081,China)
出处
《粉末冶金工业》
CAS
北大核心
2021年第4期11-15,共5页
Powder Metallurgy Industry
关键词
VIGA法制粉工艺
PREP法制粉工艺
孔洞
不锈钢粉末
vacuum induction-melting gas atomization
plasma rotating electrode process
porosity
stainless steel powder
