The steelmaking process for test hot working die steel H13 (/% : 0.36-0.38C

0.36-0.38Mn

0.89-0.91Si

0.007-0.010P

0.006-0.011S

5.10-5.15Cr

1.12-1.18Mo

0.84-0.89V) is 40 t eccentric bottom tapping arc furnace-ladle furnace refining-VD treatment-4. 65 t ingot casting process. With analysis on total oxygen and nitrogen content in liquid- T [O

]

and [ N

]

and analysis on morphology and ingredient of inclusions in steel

the cleanliness of steel H13 produced by this process flow sheet has been studied. Results show that after refining by LF-VD process the average total oxygen content in steel H13- T[O

]

is 22 x 10

-6

and the average nitrogen- [N

]

is 95 x 10

-6

the main inclusions in Φ200 mm forging are deoxidation products- alum

inium oxide with sulHdes including manganese sulfide and nitride formed by segregation ； the sizes of inclusions are mainly about 5 μm

the sizes of some inclusions can come up to about 10 μm. The steel H13 steelmaking by this flow sheet could meet the requirement for cleanliness of that steel grade.