Brass tensile strength

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. 

Table 16. Conductivity and Wrought Tensile Strength of Tin-Brasses Showing the Hardening Effect of Tin Additions...

Properties of red brass alloys are given in Table 9. The members of this group are cast using the centrifugal, continuous, investment, and sand molding methods. General tensile strengths vary from 170 to 210 MPa (25,000—30,000 psi) minimum as cast in sand molds. 

Brasses with up to 15 percent Zn are ductile but difficult to machine. Machinability improves with increasing zinc up to 36 percent Zn. Brasses with less than 20 percent Zn have corrosion resistance eqmvalent to that of copper but with better tensile strengths. Brasses with 20 to 40 percent Zn have lower corrosion resistance and are subject to dezincincation and stress-corrosion cracking, especially when ammonia is present. 

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. 

Metals, usually brass but also, for example, a more-expensive stainless steel if a higher tensile strength is needed. The insert metal must be compatible with the plastic material. For example, polyamide absorbs moisture, which leads to the steel rusting copper is a oxidation catalyst for polyolefins zinc, aluminium and brass are not compatible with polyacetals... 

Figure 5.18 Influence of annealing temperature on tensile strength and ductility of a brass alloy. Grain structures during recovery, recrystallization, and grain growth are shown schematically. Reprinted, by permission, from W. Callister, Materials Science and Engineering An Introduction, 5th ed., p. 175. Copyright 2000 by John WUey Sons, Inc.

When lead is added to brass up to about 4%. improved machinabtlity results. The lead has practically no effect on tensile strength or hardness. However, for cold-worked materials, lead does lower ductility and shear strength. 

The addition of cerium to brass is harmful, since it increases the number of leaky castings and lowers both tensile strength and ductility. Cerium forms many other alloys. Tin mixes with it in all proportions,2 forming pyrophoric alloys up to 80 per cent tin. The hardest and most pyrophoric alloy contains 30 per cent tin, and those with low tin content are not very stable in the air. 

For many plastics the use of molded metal inserts is not satisfactory because of the excessive stress produced. As an example, polystyrene with brass inserts on cooling from the molding temperature of 160 to 20°C produces a strain of (70-17)X10 X(160 - 20) or 0.0074. For an elastic modulus of 0.46 X10 psi (3.2 Gpa), the internal stresses become 3,400 psi (23 Mpa). The presence of this much internal stress renders the part useless, since the tensile strength of polystyrene is only 3,600 psi (25 Mpa). 

Green to bluish black, iridescent crystals. Soluble in fused alkali hydroxides. Abrasives best suited for grinding low-tensile-strength materials such as cast iron, brass, bronze, marble, concrete, stone and glass, optica structural, and wear-resistant components. Corroded by molten metals such as Na, Mg, Al, Zn, Fe, Sn, Rb, and Bi. Resistant to oxidation in air up to 1650°C. Maximum operating temperature of 2000°C in reducing or inert atmosphere. 

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