發(fā)布時間：2019-04-22 07:51

【摘要】：Cr13型馬氏體不銹鋼因具有較高的硬度和較強的耐腐蝕性能,已成為主要的耐蝕性塑料模具材料,并已用于制造高端、精密注塑模具。熱處理工藝不僅對馬氏體耐蝕塑料模具鋼的力學(xué)性能有重要影響,還將影響其耐點蝕性能。因此,研究熱處理工藝對Cr13型塑料模具鋼耐點蝕性能的影響規(guī)律對提高注塑模具的使用壽命有重大意義。本論文以國產(chǎn)30Cr13和進口Stavax ESR鋼為研究材料,采用先進材料分析技術(shù)研究了不同熱處理工藝對Cr13型塑料模具鋼的顯微組織演變的影響,并利用電化學(xué)實驗方法分析研究了不同熱處理工藝對Cr13型塑料模具鋼的耐蝕性影響規(guī)律。研究結(jié)果表明,淬火態(tài)Cr13型塑料模具鋼的耐點蝕性能隨著奧氏體化溫度的提高而提高。降低淬火后存留于Cr13型塑料模具鋼基體中的富Cr未溶M_(23)C_6碳化物的含量有利于提高該類型塑料模具鋼的耐點蝕性能。另外,提高鋼材潔凈度,降低鋼中TiN夾雜物含量,有利于提高Cr13型塑料模具鋼的耐點蝕性能。300℃回火后,Cr13型塑料模具鋼基體析出Cr含量與基體相近的M3C型回火碳化物,由于碳化物/基體界面的畸變所導(dǎo)致的內(nèi)應(yīng)力而使材料的點蝕電位小幅度降低。在500℃回火時,該類鋼基體中有大量富Cr納米級M_(23)C_6相析出,碳化物/基體界面處由于出現(xiàn)貧Cr區(qū)而成為點蝕起始的敏感區(qū)域,且碳化物顆粒間距極小,極大地破壞了Cr13型塑料模具鋼表面連續(xù)性鈍化膜的形成,使其在腐蝕性環(huán)境中由于失去鈍化而耐蝕性急劇降低。回火溫度提高至650℃后,Cr13型塑料模具鋼基體中析出大量富Cr的微米尺寸M_(23)C_6碳化物,該類M_(23)C_6碳化物晶粒間距較大,因而650℃回火試樣依然保持鈍化特性,但其點蝕電位明顯低于淬火態(tài)和300℃回火試樣。“淬火-配分(QP)”熱處理工藝可使Cr13型塑料模具鋼中含有一定量殘余奧氏體,并抑制了M_(23)C_6碳化物的析出,從而提高了Cr13型塑料模具鋼的耐點蝕性能,使該類塑料模具鋼不出現(xiàn)“失鈍”現(xiàn)象。當QP處理的Cr13型塑料模具鋼的殘余奧氏體含量在8 vol.%~10 vol.%時,殘余奧氏體在鋼基體中主要以薄膜狀分布于馬氏體板條間,此時Cr13型塑料模具鋼的點蝕電位較高,與淬火態(tài)鋼相近。而當殘余奧氏體含量低于6 vol.%和高于13 vol.%時,QP處理的Cr13型塑料模具鋼的耐點蝕性能較低,與350~450℃回火試樣處于相近水平。
[Abstract]:Due to its high hardness and corrosion resistance, Cr13 martensite stainless steel has become the main corrosion-resistant plastic mold material, and has been used in the manufacture of high-end, precision injection molds. Heat treatment not only has an important effect on the mechanical properties of martensite corrosion resistant plastic die steel, but also affects the pitting corrosion resistance of martensite corrosion resistant plastic die steel. Therefore, it is of great significance to study the influence of heat treatment on the pitting corrosion resistance of Cr13 plastic mould steel to improve the service life of injection mould. In this paper, using domestic 30Cr13 and imported Stavax ESR steel as research materials, the effect of different heat treatment processes on microstructure evolution of Cr13 plastic die steel was studied by means of advanced material analysis technology. The influence of different heat treatment processes on corrosion resistance of Cr13 plastic die steel was studied by electrochemical experiment. The results show that the pitting corrosion resistance of quenched Cr13 plastic die steel increases with the increase of austenitizing temperature. Reducing the content of Cr-rich M23 C _ 2O _ 6 carbides in Cr13 plastic die steel after quenching is beneficial to the improvement of pitting corrosion resistance of this type of plastic die steel. In addition, increasing the cleanliness of steel and reducing the content of TiN inclusion in steel are beneficial to the improvement of pitting corrosion resistance of Cr13 plastic die steel. After tempering at 300 鈩，

本文編號：2462648