Possibility of Zinc Embrittlement in Fire

ABSTRACT Zinc embrittlement is known as a kind of liquid metal embrittlement, a phenomenon where austenitic stainless steel and nickel alloy becomes brittle and/or cracks when it comes in contact with molten zinc. Zinc embrittlement can occur due to poor design and/or construction, but this study is focusing on the fire case. In the fire case, galvanized steel is heated by flame, and when molten zinc drops on austenitic stainless steel, some plant owners believe the zinc embrittlement will occur. In order to prevent zinc embrittlement, some plant owners request shields to protect austenitic stainless steel piping and equipment that are located in close proximity to and, in particular, beneath galvanized steel structures, piping or equipment. However, it is not proven that a molten zinc drop can cause zinc embrittlement without the direct contact between galvanized steel and austenitic stainless steel. In this study, laboratory tests and a pool fire simulation test were carried out to confirm whether zinc embrittlement occurs by fire without the direct contact between galvanized steel and austenitic stainless steel. As a result, it turned out that the risk of zinc embrittlement in fire case was very low without the direct contact of galvanized steel materials to austenitic stainless steel materials.