Fabrication of Clad Plate (Continued)

Shearing, Punching and Machining

Shearing and punching should be done with the cladding side up in order that the burr occurs on the backing steel side. Layout may be done on the cladding side. Shearing limits are essentially the same as for carbon steel.

If the sheared clad plates are to be welding, consideration should be given to shear droop. For machined edges, or when full alloy welding is employed, this effect is of no consequence. However, if the shear droop is to be removed, allowances up to 1/8-inch should be made.

Clad steels can be machined and drilled using sharp tools and firm feeds with tool speeds slightly slower than those used for carbon steel. Drilling should be done from the cladding side. With work hardenable stainless cladding, tools should continually traverse the stainless surface.

Forming

Roll-bonded clad plates are readily formed, hot or cold, in much the same manner as solid carbon or alloy steel. Prior to forming, all working surfaces of the plate and machine must be free of loose scale, steel particles and shop dirt to prevent pitting and embedding of foreign material in the plate.

Hot forming may be performed using conventional equipment, however, care must be exercised to maintain backing steel properties and corrosion resistance of the cladding. Furnace atmosphere is important. Reducing conditions should be avoided on stainless clad to prevent carburizing conditions that might impair corrosion resistance.

In contrast, materials cladded with nickel, INCONEL� and MONEL� should be heated in reducing atmosphere furnaces. More conventional practices for heating clad products, such as low sulfur fuels, removing grease, paint and other marking materials and, however possible, heating with the cladding side up, are also recommended. Heating temperatures normally augment the heat treatment given clad steels at the mill, with the same schedules used as would be for carbon or alloy steel. Successful forming has been performed in the normalizing range of 1550�F--1750�F, or from the solution annealing temperature, if applicable, which will vary with the cladding alloy. Care should be exercised to avoid excessive heating in the sensitizing range for cladding alloys subject to that condition. When mill heat treatments are affected, restoration by following the conditions reported on the mill certifications can be accomplished. Consult BLP for specific technical assistance.

For cold forming applications, special attention should be paid to the condition of the plate edges, with flame cut surfaces machined or softened and notches or rough cuts conditioned prior to fabrication. Formability of the composite plate will be dependent on the ductility of the backing and the cladding. It will not be affected by the bond characteristics under normal forming conditions. In the presence of excessive stress or strain, as in the cold forming of heads where repeated blows or spinning operations are often encountered, extra precautions are recommended because of clad's high value. Clad heads are successfully produced using conventional or proprietary methods. Consult BLP for specific technical assistance if your applications involve severe cold forming.

INCONEL^� and MONEL^�  are trademarks of   INCO