The metal industry is one of the most important consumers of energy. Energy is required for cutting, heating and melting applications. Both ferrous (iron and steel) and non-ferrous (aluminium, copper, zinc, lead, tin etc) metals are frequently treated and cast into shapes by melting and then pouring into suitable patterns/moulds. Heat treatment of metals is … Continue reading “Metals”
The metal industry is one of the most important consumers of energy. Energy is required for cutting, heating and melting applications.
Both ferrous (iron and steel) and non-ferrous (aluminium, copper, zinc, lead, tin etc) metals are frequently treated and cast into shapes by melting and then pouring into suitable patterns/moulds.
Heat treatment of metals is done through a process called annealing. This process is used to upsurge ductility and reduce the rigidity of a material. The change in the metal is brought about by reduction of dislocations in the structure of the material being annealed. Annealing is often done after the material has undergone a cold working process to prevent it from brittle failure or to make it more formable for subsequent operations. It is carried out in long ovens (tunnel ovens called “lehrs”) where the metals travel through a steel conveyor belt. Gas is used for direct firing and for temperature control as it is an ideal fuel for efficiently meeting the requirements of temperature regulation and high product quality.
In metal cutting, gas provides the perfect temperature required to provide clean cuts. Using gas also helps in achieving homogeneity as it provides flame stability, constant pressure and fuel consistency. This helps to strike a profitable balance between fuel price and product quality. Gas easily meets industry requirements and is an excellent fuel option in forging, wire drawing, casting, hole-piercing and the welding of non-ferrous metals.
Melting is an important but energy-intensive industrial process. Gas is constantly used for melting in foundries. Metals such as aluminium, copper, iron, gold, silver have to be melted and remoulded to serve various purposes. The two main apparatuses used to melt metals are blowtorches and furnaces (crucible/pot furnaces, rotary drum furnaces and reverberatory furnaces), whose usage depends not only on processing scale but also on the metal to be melted. The melting points of metals can range from as low as – 39o C (Mercury) to as high as 3422o C (Tungsten). Gas is the most suitable fuel to control the heating up process as well as increase temperatures in a manner that accommodates structure expansion.
- Gas ignites as soon as the burner on the furnace is set and the gas valve is opened.
- Gas is a clean fuel that requires no manual reloading during furnace runs since fresh gas enters the burner constantly.
- Propane is widely available.
- It is best suited for melting metals regardless of type and size.
Moulding is a process of shaping liquid (or pliable) raw material such as plastic, glass, metal or ceramic using a rigid frame/ mould.
Moulds are predominantly made from metal. Gas is used for preheating of the metallic mould. This is done to in order to ensure that the heat of the metal is not lost as well as for safety issues that may arise due to difference in the temperate of the mould vs. that of the melted metal.
Gas is the best option while working with sand moulds. It can be used to power small ovens (which dry the sand cores) and manual torches (used to dry the inner surface of the mould).
Soldering, Welding, Flame Cutting and Brazing
The above mentioned are processes used in the industries like building, jewellery, manufacturing, road construction, refrigeration, plumbing, power, leather etc. Examples wherein the processes are used are mentioned below.
Example 1: In the jewellery making, nearly every ornamental piece requires joining metal together using heat. Thus, making a gas soldering torch is one of the most important pieces of equipment. In addition to jewellery making, gas torches are frequently employed for soldering copper and water pipes. They can also be used for low temperature welding applications and brazing dissimilar metals together.
Example 2: In the construction industry, gas (at times mixed with acetylene) is used cast iron and weld steel. It is also used in cutting of most carbon steel because it cuts through across layers and does not create air gaps, leaving no slag on the steel. Gas is effective to use when a greater nozzle to workpiece distance is required as it reduces the risk of molten metal splashing back onto the nozzle which can cause a “backfire”.
Since gas is a clean-burning fuel the working environment remains free from polluting gases thus is conducive for workmen.
- Flux-free brazing of joints for high integrity and strength.
- Maximum flame temperature of propane in oxygen is about 2820oC or 5110oF
- Maximum flame temperature of propane in air is about 1995 °C or 3623 °F.
- It is economical setup.
- It is a non-toxic, easily detectable, stable, high-energy fuel.
- Environmentally friendly.
- On a profile-cutting machine, oxy-propane gives quick clean cuts on thick plate.
- Easily combustible.
- Portable with clean burning characteristics and a high calorific value.