and frequently used for decorative trim and equipment subjected  to  high  pressures  and  temperatures. Martensitic Chromium.— These steels are mag- netic and are readily hardened by heat treatment. They contain 12% to 18% chromium, 0.15% to 1.2% carbon, and up to 2.5% nickel. This group is used where high strength, corrosion resistance, and ductility are required. ALLOY STEELS.— Steels that derive their prop- erties primarily from the presence of some alloying element  other  than  carbon  are  called  ALLOYS  or  AL- LOY STEELS. Note, however, that alloy steels always contain traces of other elements. Among the more com- mon alloying elements are nickel, chromium, vana- dium,  silicon,  and  tungsten.  One  or  more  of  these elements may be added to the steel during the manufac- turing process to produce the desired characteristics. Alloy steels may be produced in structural sections, sheets, plates, and bars for use in the “as-rolled” condi- tion.  Better  physical  properties  are  obtained  with  these steels  than  are  possible  with  hot-rolled  carbon  steels. These alloys are used in structures where the strength of material is especially important. Bridge members, rail- road cars, dump bodies, dozer blades, and crane booms are made from alloy steel. Some of the common alloy steels  are  briefly  described  in  the  paragraphs  below. Nickel Steels.— These steels contain from 3.5% nickel  to  5%  nickel.  The  nickel  increases  the  strength and  toughness  of  these  steels.  Nickel  steel  containing more than 5% nickel has an increased resistance to corrosion and scale. Nickel steel is used in the manufac- ture  of  aircraft  parts,  such  as  propellers  and  airframe support  members. Chromium Steels.— These steels have chromium added to improve hardening ability, wear resistance, and strength. These steels contain between 0.20% to 0.75% chromium and 0.45% carbon or more. Some of these steels are so highly resistant to wear that they are used for the races and balls in antifriction bearings. Chro- mium steels are highly resistant to corrosion and to scale. Chrome Vanadium Steel.— This steel has the maximum amount of strength with the least amount of weight. Steels of this type contain from 0.15% to 0.25% vanadium, 0.6% to 1.5% chromium, and 0.1% to 0.6% carbon. Common uses are for crankshafts, gears, axles, and other items that require high strength. This steel is also used in the manufacture of high-quality hand tools, such as wrenches and sockets. Tungsten  Steel.— This is a special alloy that has the property of red hardness. This is the ability to continue to cut after it becomes red-hot. A good grade of this steel contains from 13% to 19% tungsten, 1% to 2% vana- dium, 3% to 5% chromium, and 0.6% to 0.8% carbon. Because this alloy is expensive to produce, its use is largely restricted to the manufacture of drills, lathe tools, milling  cutters,  and  similar  cutting  tools. Molybdenum.— This is often used as an alloying agent  for  steel  in  combination  with  chromium  and nickel. The molybdenum adds toughness to the steel. It can be used in place of tungsten to make the cheaper grades  of  high-speed  steel  and  in  carbon  molybdenum high-pressure  tubing. Manganese Steels.— The amount of manganese used depends upon the properties desired in the finished product. Small amounts of manganese produce strong, free-machining steels. Larger amounts (between 2% and 10%) produce a somewhat brittle steel, while still larger amounts (11% to 14%) produce a steel that is tough and very resistant to wear after proper heat treat- ment. NONFERROUS METALS Nonferrous metals contain either no iron or only insignificant amounts used as an alloy. Some of the more common  nonferrous  metals  Steelworkers  work  with  are as  follows:  copper,  brass,  bronze,  copper-nickel  alloys, lead,  zinc,  tin,  aluminum,  and  Duralumin. NOTE: These metals are nonmagnetic. Copper This metal and its alloys have many desirable prop- erties. Among the commercial metals, it is one of the most  popular.  Copper  is  ductile,  malleable,  hard,  tough, strong, wear resistant, machinable, weldable, and cor- rosion resistant. It also has high-tensile strength, fatigue strength, and thermal and electrical conductivity. Cop- per is one of the easier metals to work with but be careful because  it  easily  becomes  work-hardened;  however,  this condition can be remedied by heating it to a cherry red and then letting it cool. This process, called annealing, restores  it  to  a  softened  condition.  Annealing  and  sof- tening  are  the  only  heat-treating  procedures  that  apply to copper. Seams in copper are joined by riveting, silver brazing, bronze brazing, soft soldering, gas welding, or electrical arc welding. Copper is frequently used to give a protective coating to sheets and rods and to make ball floats, containers, and soldering coppers. 1-6