Alloy raj yog ib hom seamless steel raj, muab faib ua cov qauv seamless raj thiab siab kub kub resistant alloy raj. Feem ntau sib txawv ntawm cov qauv tsim thiab kev lag luam ntawm cov hlau alloy, annealed thiab tempered alloy raj hloov cov khoom siv kho tshuab. Ua tau raws li qhov yuav tsum tau ua. Nws qhov kev ua tau zoo siab dua li cov yeeb nkab seamless steel zoo tib yam, cov tshuaj muaj pes tsawg leeg muaj Cr ntau dua, yog li nws muaj qhov kub thiab txias tsis kam, tsis kub tsis kam thiab corrosion kuj. Ordinary carbon seamless raj tsis muaj alloy lossis me me ntawm alloy. Alloy raj yog siv dav hauv roj av, aerospace, tshuaj, hluav taws xob, boiler, tub rog thiab lwm yam lag luam, vim hais tias cov khoom siv ntawm cov hlau alloy tube yog qhov sib txawv, yooj yim kho.

Alloy steel yeeb nkab yog tsuas yog siv nyob rau hauv fais fab nroj tsuag, nuclear fais fab nroj tsuag, high-pressure boiler, high kub superheater, reheater thiab lwm yam kev kub siab thiab kub kub kav thiab khoom siv. Nws yog ua los ntawm cov pa roj carbon zoo, alloy cov qauv hlau thiab cov hlau tsis muaj cua sov los ntawm kub dov (extrusion, expansion) lossis txias dov (kos duab).