AISC: No Crisis in HSS Supply, Buyer Should Be Aware of Suppliers, Quality Control
December 18, 2007 // Published as a news service by IHS
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After reviewing data about the quality of imported hollow structural section (HSS), the American Institute of Steel Construction Inc. (AISC) said that no crisis exists with regard to the HSS supply. However, buyers still should evaluate their HSS suppliers and practice quality control (QC).
AISC conducted the review in response to questions that arose several months ago regarding the mechanical properties of imported HSS and the credibility and reliability of the documentation provided when the imported products entered the U.S. and Canada.
The data AISC collected represented a limited number of tests on mechanical and chemical properties. AISC staff and industry materials consultants reviewed this data and noted the following:
- Many of the tests were performed to different procedures and protocols than are required for HSS in American Society for Testing and Materials (ASTM) A500 and therefore lacked uniformity for analysis.
- Testing speeds varied significantly among the tests that were reported to AISC.
- There was no control or tracking of the location of test specimens as to what position they came from in the width and length of the coil.
Despite these factors, each of which will induce significant variations in the testing results, the mean of the independent test results was similar to the mean of the material test report (MTR) values, AISC said.
As should be expected, these factors resulted in a higher standard of deviation. Accordingly, AISC concluded that this does not represent a building code issue.
"Perhaps the most important recommendation is that the buyer should know and evaluate their material supply chain," said Roger Ferch, P.E., AISC president. "As with any other purchase, don't just look at the quoted price but also consider the quality, reputation and experience of the supplier."
The buyer also should verify that the material and its documentation meet ASTM A500 requirements when it is received. A few MTRs AISC received were for material that had been accepted by the purchaser with metric values reported on the MTRs that did not meet the minimum ASTM requirements. Such deviations can be avoided with simple receiving inspection of the material to ensure it is as it was ordered, according to AISC.
In addition, AISC received reports of seam weld quality concerns with imported HSS. For more information about the seam weld deficiencies that led to these concerns, go to http://www.dsa.dgs.ca.gov/labs/hss_pictures.htm. The defects in the defective material were identifiable through visual inspection.
According to AISC, the limited information that is available to date on this topic and the anecdotal nature of reports of weld seam defects leads the organization to believe there is no crisis in HSS supply and no dramatic response is necessary.
"Producer quality control is an essential part of the supply chain, and we believe that North American producers are routinely exercising good QC processes," said Louis F. Geschwindner, AISC vice president of engineering and research.
"Receiving inspection at various levels is a routine method to evaluate supplier quality control, and we believe that steel service centers and fabricators are properly performing this function," Geschwindner said. "Where a supplier is new or unknown, these reports may be cause to increase vigilance to ensure that the material they supply is acceptable."
Source: American Institute of Steel Construction Inc. (AISC).