Metals The metal industry is indeed one of the most important consumers of energy. Energy is generally 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 injection or pouring into suitable patterns … Continue reading “Metals”
The metal industry is indeed one of the most important consumers of energy. Energy is generally 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 injection or pouring into suitable patterns and moulds.
Heat treatment of metals involves heating and cooling of the solid metal with the aim of modifying its physical properties through a process called annealing. Annealing is a process of slowly cooling glass to relieve internal stresses after manufacture. The cooling rate is very important because strains will be set up in the glass if it cools at undesired rate. Annealing is conducted most times in long ovens (‘tunnel’ ovens called “lehrs”) with the glass traveling through on a steel conveyor belt. Gas is used for direct firing and for finer temperature control.
Gas is an ideal fuel for efficiently meeting the requirements of temperature regulation and high product quality.
In metal cutting, Gas provides stable high temperature required to provide clean cuts. Gas ensures that melting operations are homogeneous due to its constant temperature control.
Gas is a far superior fuel when compared to the other heavy fuels due to its flexibility, flame stability, dependable constant pressure and fuel consistency. It helps to improve the cost of operation thus striking an economic balance between fuel price and product quality.
Gas is clean burning – leaving no residue of sulphur, lead and carbon. This leads to minimum scaling losses. It is safe and poses no risk of overheating or blow back.
The fuel is used extensively in steel making and finishing processes.
It easily meets industry requirements and has been a favourite of steel manufacturers over the years to satisfy all their fuel needs. It also offers good applications in forging, wire drawing, casting as well as steel cutting, hole-piercing and the welding of non-ferrous metals.
Melting is another important but energy-intensive industrial process.
Gas is constantly used for melting in metal industry foundries as well as in other industries such as the glass, construction and asphalting industries.
Ferrous and non-ferrous metals such as aluminium, copper, iron, gold, silver and even substances such as glass have to be melted and remoulded to serve various purposes.
The two main types of apparatus used to melt metals are blowtorches and furnaces; whose respective use depends not only on processing scale but also on the metal to be melted.
Glass works are high-temperature, energy intensive processes where temperatures in the order of 1350-1600oC are required in order to liquefy glass. A high-grade fuel like Gas is the most suitable to control the heating up process and then increase temperatures in a manner that accommodates structure expansion.
Melting furnaces are generally classified based on energy source for heat generation.
- Fuel-combustion based furnaces.
- Electricity-to-heat furnaces
The main types of gas-fuelled melting furnaces are crucible / pot furnaces, rotary drum furnaces and reverberatory furnaces.
Gas burners are popularly used for melting metals with melting points up to 1100oC (copper, silver, gold)
- Gas ignites as soon as the burner on the furnace is set and the gas valve is opened. Ignition is instant.
- Gas burns cleanly all the time and requires no manual reloading during furnace runs since fresh Gas enters the burner constantly.
- Propane is widely available due to its vast range of applications.
- It is suitable for melting metals of all types and sizes
Moulding is a process of shaping liquid (or pliable) raw material such as plastic, glass, metal or ceramic using a rigid frame (a mould).
Moulds are predominantly made from metal and Gas provides several applications in the formation and use of permanent metallic moulds.
Gas firing with air or oxygen is used for preheating of the metallic mould. This prevents the loss of the first amounts of raw material due to cold mould.
Gas is also useful where sand is the mould material. It is used to power small ovens which dry the sand cores, as well as the manual torches used to dry the inner surface of the mould.
It is furthermore used for sand-recovery where a Gas powered (rotary drum) kiln can be used to evaporate and incinerate sand additives such as phenolic resins.
Soldering, Welding, Flame Cutting
Soldering, welding, flame cutting, and brazing are processes widely used in the building, manufacturing, road construction, refrigeration, plumbing, power, leather industries and more. Especially for copper where Gas is used widely, the two most common methods of joining copper tube and fittings have been soldering and brazing using varying degree of heat. Gas’s heat capacity is an ideal fuel for soldering and brazing within the air conditioning, plumbing, refrigeration and hydraulics industries.
In the jewellery making, Gas soldering torch is one of the most important pieces of equipment. Nearly every ornamental piece requires joining metal together using heat. In this application, several variants of the Gas spectrum are used for different purposes in jewellery making. In addition to jewellery making, Gas torches are frequently employed for soldering copper and water pipes. It can also be used for some low temperature welding applications, as well as for brazing dissimilar metals together.
In the construction industry, Gas is used to weld steel for constructing residential and commercial buildings. It is also used to cast iron and weld steel during the construction of rail tracks. Some also mix acetylene and Gas for welding steel and iron cast. Gas is also used in cutting of most carbon steel because it cuts through across layers and jumps air gaps with ease, leaving no slag on the steel. It can tolerate a greater nozzle to workpiece distance which reduces the risk of molten metal splashing back onto the nozzle and causing a “backfire”.
Gas is a clean-burning fuel that doesn’t cause metal to oxidise as readily as acetylene. It is also cheaper to buy and setup. Furthermore, the working also environment remains free from polluting gases and thus is conducive for workmen.
- Very clean, superior,
- Flux-free braze joints of 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 more economical to buy and setup.
- It is a non-toxic, easily detectable, stable, high-energy fuel.
- Environmentally friendly.
- On a profile-cutting machine, oxy-propane gives fast, clean cuts on thick plate
- Easily combustible.
- Portable with clean burning characteristics and a high calorific value