The production process of P92 heat-resistant steel continuous casting billets （

<math id="M4"><mi>ϕ</mi></math>

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014197&type=

2.87866688

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014199&type=

2.03200006

380 mm-

<math id="M5"><mi>ϕ</mi></math>

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014197&type=

2.87866688

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014199&type=

2.03200006

1 000 mm） for ultra-supercritical boiler tubes was introduced by Spec

ial Steel Company of Ma'anshan Iron and Steel， the process involved electric furnace/converter steelmaking → LF refining → RH vacuum degassing → CCM continuous casting. By adopting processes such as charging refined materials in the furnace， full-process foam slag operation in electric arc furnaces， EBT alloying during steel tapping， white slag operations during refining， electromagnetic stirring in three stages of continuous casting， and full-process protective pouring，

w

［Cr］ was kept at ≤8.75%，

w

［Ni］ at ≥0.20%， and

w

［N］ at ≥0.050%. This effectively controlled high-temperature ferrite. By controlling the white slag time to be ≥20 min， the

w

［T.O］ ≤0.003 0% of the billet is maintained， with low levels of various microstructure defects and center cracks in the continuous casting billet being ≤2.0 grade.The final ultra-supercritical boiler tubes exhibited high purity， with A， B， C， D， coarse series inclusions at level ≤1.0， and A， B， C， D fine series and DS inclusions at level ≤1.5. Using a

<math id="M6"><mi>ϕ</mi></math>

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014197&type=

2.87866688

https://html.publish.founderss.cn/rc-pub/api/common/picture?pictureId=96014199&type=

2.03200006

500 mm P92 continuous casting billet， after oblique rolling into tube and heat treatment at 1 040 ℃ normalizing + 760 ℃ tempering， the steel tube demonstrated room temperature tensile strength ≥730 MPa， high-temperature tensile strength at 625 ℃ ≥280 MPa， yield strength ≥260 MPa， and an extrapolated value of 100 000 hour creep strength of 96.9 MPa （110 MPa for 25 200 hours without failure）， meeting the metallurgical quality requirements of manufacturers producing ultra-

supercritical boiler tubes.