闻小德, 吕安明, 刘利, et al. Analysis on Nondestructive Examination Defects of Steel S355NL for Wind Power Flange and Process Improvement[J]. Special Steel, 2016, 37(2): 36-38.
闻小德, 吕安明, 刘利, et al. Analysis on Nondestructive Examination Defects of Steel S355NL for Wind Power Flange and Process Improvement[J]. Special Steel, 2016, 37(2): 36-38.DOI:
风电法兰用钢S355NL(/%:0.14~0.48C,0.15~0.40Si,1.30~1.60Mn,≤0.013P,≤0.005S,0.04~0.12V,0.03~0.05Nb,≤0.009Ti,≤0.30Cr,≤0.50Ni,≤0.20Cu,≤0.10Mo,≥0.020Alt)的冶金流程为100t UHP EAF—LF—VD—Φ650 mm
Φ800 mm坯CC工艺。该钢1~2 mm裂纹探伤不合格的分析结果表明
其主要原因为氧的铝类夹杂和铸坯疏松缺陷所致。通过在LF终点喂钙线0.45 kg/t
VD处理时间由原25 min增至27 min
降低钢中[N
]
至78×10
-6
~82×10
-6
[H
]
为1.1×10
-6
~1.3×10
-6
[O
]
为12×10
-6
~15×10
-6
软吹氩气流量由2×25L/min降至2×20 L/min
时间≥12 min
降低钢水过热度5℃等工艺措施
使铸坯锻造后的探伤合格率超过99%。
Abstract
The metallurgical flowsheet for steel S355NL for wind power flange (/% : 0.14-0.48C
0.15-0.40Si
1.30-1.60Mn
≤0.013P
≤0.005S
0.04-0.12V
0.03-0.05Nb
≤0.009Ti
≤0.30Cr
≤0.50Ni
≤0.20Cu
≤0.10Mo
≥0.020Alt) is 100t UHP EAF-LF-VD-Φ650 mm
Φ800 mm bloom CC process. The results of analysis on unqualified steel by nondestructive examination due to 1-2 mm cracks show that cracks are mainly caused by alumina inclusions and casting bloom porosity defects. By the process measures including feeding calcium wire 0.45 kg/t at end LF
increasing VD treading time to 27 min from original 25 min
decreasing the [N
]
in steel to 78 x 10
-6
-82 x
10
-6
the [H
]
to
1.1 x
10
-6
-1.3 x
10
-6
and the [O
]
to 12 x
10
-6
- 15 x
10
-6
decreasing the soft argon blowing rate to 2 x 20 L/min from 2 x 25 L/min
time≥12 min and decreasing the liquid overheating extent by 5℃
the qualified ratio of steel forged from casting bloom is more than 99%.