鈷基合金是在鈷鉻合金中熔入適量的鎢和碳,鎢的加入使鈷基體進(jìn)一步固溶強(qiáng)化。碳在鈷中的溶解度很小,因而加入的碳和過(guò)量的鎢形成 WC,W2C,M6C等碳化物,這些硬質(zhì)相彌散分布在鈷基體中,產(chǎn)生析出強(qiáng)化作用,使該類合金在800℃高溫下,仍能保持優(yōu)異的高溫強(qiáng)度和高溫硬度,因此鈷、鉻、鎢、碳合金具有優(yōu)異耐高溫磨損、抗高溫氧化和熱疲勞等綜合性能。
Cobalt-base alloy is produced by melting suitable amount of tungsten and carbon into the cobalt-chrome alloy, which will enhance the solid-solution strengthening of the cobalt base. For the low solubility of carbon in cobalt, the added carbon and superfluous tungsten may generate WC,W2C,M6C and other carbides. The hard materials distribute in the cobalt base and strengthen the separation process, thus the alloy can maintain excellent intension and rigidity under high temperature of 800℃. Thus, the cobalt, chrome, tungsten and carbon alloy have integrated performance of preventing the high temperature wear, oxidation and thermal fatigue.
鈷在417℃溫度以下,為密排六方結(jié)構(gòu),具有低的摩擦系數(shù),而具有很好的耐磨性。在417℃溫度時(shí)發(fā)生由密排六方晶體,向面心立方晶體的轉(zhuǎn)變,而產(chǎn)生體積應(yīng)力。因此在噴焊時(shí)一般均需將被焊工件預(yù)熱到500℃~600℃,以防鈷基焊層開(kāi)裂。
Below 417℃,cobalt is in dense-hexagonal structure,it has lower frictional coefficient and sound wear resistance. The structure of cobalt will change from dense-hexagonal crystal into face-center-cubic structure under 417℃. The volume stress may appear. Therefore, the welding pieces should be warmed up to 500℃~600℃ to avoid the crack for cobalt-base