steel pipe for construction 1)OD:4mm-50mm; WT ... name-main material-standard-usessize range(mm)stainless steel pipe 0Cr18Ni9 (304),00Cr19Ni10 (304L),00Cr17Ni14MO2(316L),00Cr17Ni12MO2( ... 5 line pipe 5L GR.B, X52,X60 API-for petroleum,natural gas, industrial dilivery(gas,water,oil) ... iron pipe-ironGB/T13295-2003 ISO2531/2003- Public works, mining, textile, electric power, boilers, drinking water, machinery ...