High-tensile brass

High-tensile brasses are a-0 (or, occasionally, /3) alloys containing up to 5% A1 and 1-2% of one or more of the following Sn, Pb, Fe, Mn. These alloys also are used in both wrought and cast form. 

In the tests described by Tracy, a high-tensile brass suffered severe dezinc-ification (Table 4.11). The loss in tensile strength for this material was 100% and for a non-arsenical 70/30 brass 54% no other material lost more than 23% during 20 years exposure. In Mattsson and Holm s tests the highest corrosion rates were shown by some of the brasses. Dezincification caused losses of tensile strength of up to 32% for a P brass and up to 12% for some of the a-P brasses no other materials lost more than 5% in 7 years. Dezinc-ification, but to a lesser degree, occurred also in the a brasses tested, even in a material with as high a copper content as 92%. Incorporation of arsenic in the a brasses consistently prevented dezincification only in marine atmospheres. 

High tensile brass C38500 57Cu-40Zn 138 414 30 88-109 8.620... 

High tensile brass (architectural bronze) C38500 57Cu-40Zn-3Pb 8350 138 414 30 95 990 88-109 21.0 8.620... 

High-tensile brass C86500 58Cu-39Zn-l.3Fe-lAl-0.5Mne 8300 105 193 490 30 100-130 862-880 87 373 20.3 8.41... 

If the alloys to be analysed contain not only oxides hard to reduce, but also fairly volatile alloying elements, for example high tensile brass, the most appropriate procedure is first to volatilize the volatile elements in vacuo, and only then to submit the residue to analysis by reducing fusion. 

Under the reaction conditions described for reducing fusion, all zinc oxide is reduced without difficulty, as has been demonstrated. If aluminium oxide is present (high tensile brass), it is also determined, but requires reduction times of 9 to 30 minutes. 

Drums. Typical selection for the number of dmms used in the various appHcations is two to four for cobbers, one or two for roughers, and two or three for finishers. The inner dmm sheU, usually 3 mm thick, is specified Series 302 or 304 stainless steel. Dmm heads are usually of high tensile strength aluminum alloy or brass. Recessed head bolt constmction having an effective seal is specified. 

The wire beads used are produced from a combination of multi-strand copper, zinc or brass coated high-tensile steel wires. The required number of wires are formed into the required shape and then passed through a cross-head extruder to be coated with rubber compound. The coated wire layers are then formed into a coiled ring and the free wire ends secured together. For certain heavy duty applications use is made of either a light weight rubberised fabric or a small fibre filled rubber sheet to cover the joint area. In some cases the bead construction is also partially vulcanised. 

The bead is constructed from a number of turns or coils of high tensile steel wire coated with copper and brass to ensure good adhesion of the rubber coating applied on it. The beads function as rigid, practically inextensible units that retain the inflated tire on the RIM. 

Braiding hoses with wires to resist high burst pressures or for external protection is common, using a braiding machine. The wires used, usually of steel, will be either zinc- or brass-coated to achieve adhesion during vulcanisation. The gauge of the wire and its tensile properties will be matched to the expected service demands for the hose. 

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