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The moisture level in timber is the most important factor in determining the incidence of corrosion. Above a threshold moisture level, wood is always acidic due to the breakdown of wood cellulose to acetic acid. Applied chemical treatments to the timber or exposure in a marine environment can increase the corrosion risk.
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Hardness testing methods, including Brinell, Vickers and Rockwell are outlined. The hardness scales, including, HB, HV, HRB ,and HRC are shown for each method and a comparison table of hardness values between these scales presented.
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Heat treatment, (tempering), of austenitic strip and wire grades for enhanced mechanical properties is referenced in BS EN 10151, (strip), and BS EN 10270-3, (wire).
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The original version of European directive 2002/95/EC effectively out-lawed stainless steels and many other materials as no lead, mercury, cadmium, hexavalent chromium, poly-brominated biphenyls (PBB) or polybrominated diphenyl ethers, (PBDE), content was to be allowed in materials that would be part of equipment ‘which is dependant on electric current in order to work properly’. This has now been rectified in the Official Journal of the European Union document C(2005) 3143, 2005/618/EC, published on 18th August 2005, allows maximum levels of 0.1% for all these, except cadmium which is 0.01%, which is the same as in the ELV directive. In stainless steels only the restrictions to the elements lead, mercury and cadmium are relevant. Commercially produced stainless steels can be expected to comply with the amended RoHS requirements, without actual values being measured or declared by the steelmaker or supplier.
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BS EN 10151, (strip), and BS EN 10272-3, (wire), for springs are outlined. The grades in each standard are tabulated and compared to the BS 5770-4 and BS 2056 which they replace, where grades such as 301S21, 301S81, 302S26, 302S25 and 305S11 were specified. Grades listed include 1.4016, 1.4021, 1.4028, 1.4031, 1.4568, (17/7 PH type), 1.4310, 1.4301, 1.4401, 1.4369, 1.4372, and 1.4568 Mechanical properties in the cold worked, (temper rolled for strip, drawn for wire), conditions are shown. Heat treated properties for precipitation hardening grade, 1.4568, wire are also shown.
