ASTM A53 is a carbon steel alloy, which can be used as structural steel or for low-pressure pipelines.ASTM A53 (ASME SA53) carbon steel pipe is a specification that covers seamless and welded black an... View MoreASTM A53 is a carbon steel alloy, which can be used as structural steel or for low-pressure pipelines.ASTM A53 (ASME SA53) carbon steel pipe is a specification that covers seamless and welded black and hot-dipped galvanized steel pipe in NPS 1/8″ to NPS 26. A53 is intended for pressure and mechanical applications and is also acceptable for ordinary uses in steam, water, gas, and airlines.