Heat and rebar indicate that the inspection will be rejected. Rebar cannot be cut, bent, or welded. It will not pass inspection, whether it is a state job or a city job. It must be shear cut and bent by hand. Then it can be welded together again to make another piece of rebar.
Heating rebar allows you to work with it before welding it. You can shape it into any form without melting it. This is useful for making sharp corners or giving it a uniform diameter when welding parts of it together. Heating also helps remove some of the hardness left from the manufacturing process so that you an get a better fit when welding joints together.
Bending rebar allows you to make shapes like angles or loops. You can't heat-bend rebar because it would damage the structure of the metal. But you can use a brake beam cutter to slice it into pieces that can then be bent by hand.
Welding rebar ensures its strength after construction has been completed. If there are any cracks in the bar during installation it will cause weak spots in the building which could lead to more serious problems later on. Cracks can be fixed by welding or brazing new bars onto existing ones.
Rebar is used in construction to provide extra support for concrete frames.
Not every rebar can be welded, especially with the exothermic welding technique, because it must be capable of heating the surface of the metal rebar to the melting point to assure adhesion. In general, only "Grade W" steel rebar may be welded. However other types of steel may be used if they are heat treated to increase their hardness.
The type of welding process used will determine whether or not a particular section of rebar can be welded. For example, oxyacetylene welding would be unsuitable for heating large sections of steel rebar enough to melt them, while electric resistance welding and laser welding could be used on any length of rebar. Of these two processes, electric resistance welding is generally considered the best option for welding steel rebar because it provides a high strength joint that looks good and performs well in service.
Welding steel rebar requires special care because the heat from the welder will affect the surrounding area. Workers should wear protective clothing (such as gloves) when welding near combustible materials or equipment. The flame from an oxyacetylene torch will also burn carbon off of steel so it cannot be used in place of an electric welder.
Since most cities require steel reinforcement for new buildings, there will usually be a supplier of rebar nearby. Rebars are sold by the ton and sometimes have labels warning against driving a truckload away before it has completely cooled.
For 30-60 seconds, use a blow torch to heat the rebar at the bending point. The metal will flex more easily if it is mildly heated. Avoid heating rebar any more than necessary because it can cause it to break down or warp.
Heating steel only heats the surface, so if you need to melt something inside the steel, like another piece of rebar, you'll have to do that before bending it too. But even then, you should cool off the hot object before removing it from the steel.
You can also heat steel by placing it in an oven for example. But again, avoid leaving objects in the oven too long because they could get damaged.
Finally, you can also use a gas burner to heat rebar. But as with any tool, heat it carefully and be sure not to burn yourself.
Bending steel rebar can be difficult work. There are many different tools available to help out, but you should avoid using a tool that is not designed to bend this kind of material. For example, a hammer will not be effective for bending rebar because it will not give it enough pressure to make a real change to its shape.