Correct

扁钢

/ piān gāng / 
Strokes

Example

As a Noun

flat steel

1
Piāngāng
扁钢
zhájī
轧机

flat-rolling mill

2
Piān
扁
gāngpī
钢坯
zhájī
轧机

slabber; slab mill

3
Piān
扁
gāngdìng
钢锭

flat/flat-shaped ingot