Bending and Forming

Bending and Forming Pipe may be bent to any radius for which the bend-arc surface will be free of cracks and substantially free of buckles. The use of bends which are creased or corrugated is permitted. Bending may be by any hot or cold method permissible within the radii and material characteristics of the pipe being bent. 

The addition of up to 0-2% of aluminium to the galvanising bath, on the other hand, depresses the formation of alloys and produces lighter and more ductile coatings, which are more suitable for galvanised sheet since they render it more amenable to bending and forming. 

Yet another option for domestic appliances is to make the appliance from precoated coil. The appliance has to be designed to minimise the problem of unprotected cut edges. Electroplated zinc-coated steel, pretreated, primed and finished with special polyester-melamine, is used. The finish is designed to be hard at room temperature, yet accept bending and forming, probably, but not necessarily, at somewhat higher temperatures (ca. 60°C). 

Heat treatment is used to avert or relieve the detrimental effects of high temperature and severe temperature gradients inherent in welding and to relieve residual stresses created by bending and forming. Provisions in para. GR-3.9 are basic practices that are suitable for most bending and forming operations but not necessarily appropriate for all service conditions. See Nonmandatory Appendix A for a discussion of when additional heat treatment should be considered. 

The goal of this chapter is not to convince you to switch to prepaint rather, the focus is to demystify prepainted metal and present some tooling ideas on bending and forming that work well and can be tailored to meet your needs. 

Hot bending and forming After hot bending and forming, heat treatment is required for P-Nos. 4, 5, 6, and lOA materials in all thicknesses. 

Heat treatment should be used to avert or relieve the detrimental effects of high temperature and severe temperature gradients inherent in welding, and to relieve residual stresses created by bending and forming. 

Plain cogs/gears, multiple or continuous bends and forms. 

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