UK Steel issues safety warning on weldability of Chinese structural steels
UK Steel, the trade body for the UK steel industry, has issued a further safety warning about the use of Chinese steel, the association tells Kallanish. The notification covers imported steel plate and sections and follows a similar warning by UK Steel in January about Chinese rebar imports (see Kallanish 16 January).
UK Steel director Ian Rodgers says, “For the past few months it has become increasingly clear that some imported steel plates and sections from China are being supplied into the UK market, which are not fully compliant with the requirements of the relevant standard.
The EU specification for structural steel explicitly states that it applies only to “non-alloy steels”, UK Steel says. To qualify as “non-alloy”, a steel must comply with strict limits on the quantity of other metallic elements it contains. This “non-alloy” classification amongst other things ensures that the steel is readily weldable without the need to apply any special welding parameters.
Recent Chinese practice involves producers adding small amounts of alloying elements to plain carbon steels. These can then be be re-classified as alloy steel to avoid local export taxes. However alloy steel plates and sections do not comply with the European standard for structural steel, the UK producers’ association says.
More importantly, these alloy additions can significantly affect the steel when being welded. Additions at these levels can cause the steel to crack on welding, a problem which may not show up until 48 hours later. A similar problem can arise with copper-alloyed steel. Again, Chinese imports have been discovered with elevated levels of copper, UK steel confirms.
Ian Rodgers warns: “It is imperative that structural steel plates and sections with elevated alloy levels are treated with great care and where possible avoided totally for applications where welding is required, as there is a heightened risk of catastrophic failure. Our advice is that customers should carefully check the alloy content of Chinese structural steel before processing it.”
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