Welding Steel Alloys

09 November 2020

The whole welding process has been maximised by numerous industries today due to its effectiveness in combining two or more parts firmly together. Welding utilises heat, pressure, or both in joining the parts. It likewise uses durable filler material so that the connection between the parts will be solid and stable. This process is basically used in combining metals, thermoplastics, and even wood.

One specific metal material that can take advantage of the welding process is a steel alloy. Steel alloy primarily contains iron and a few percent of carbon, helping it gain improvements over its strength and fracture resistance. Adding some more carbon elements to steel alloy can easily make it stronger.

Steel Alloy Classification

The overall composition and elements of steel alloy can be versatile, which allows it to be classified into different categories. Some of the basic classifications of steel alloy are as follows:

• Low-carbon Steels:Low-carbon steel is primarily comprised of up to 0.30 weight percent of carbon. This specific steel alloy can easily be welded in a room temperature environment and is known to cost less to process compared to others. Flat-rolled products take up the largest category under this classification, boasting around 0.10 weight percent of carbon and 0.4 weight percent of manganese.
• Medium-carbon Steels: Medium-carbon steels, alternatively, have around 0.30 to 0.60 weight percent of carbon and around 0.60 to 1.65 weight percent of manganese. This overall composition of medium-carbon steels allows them to be utilised in quenched and tempered condition. Weld cracking can be prevented on these steel alloys through preheating and post-heat treatment.
• High-carbon Steels: High-carbon steels have 0.60 to 1.00 weight percent of carbon and manganese of around 0.30 to 0.90 weight percent. This group of steel alloy can be difficult to weld as it easily develops hard and brittle martensite phase once it is cooled from welding. Therefore, high-carbon steels are frequently subjected to thorough preheating and post-heating processes.

Welding Considerations

When welding steel alloys, numerous welding considerations must be determined first. The following are some of the most important welding considerations whenever steel alloys are being welded.

• Carbon Content: Knowing the carbon content of steel alloys can determine how they can be welded. Low-carbon steels can be welded easily in a room temperature environment. Medium-carbon steels, alternatively, must undergo pre-heat and post-heat treatment so they will not crack while welding. Ultimately, high-carbon steels must be subjected to thorough preheating and post-heating processes first before welding them. They must also work with special filler materials.
• Carbon Equivalency: The carbon equivalency formula of steel alloys must also be considered when welding them. Aside from carbon, other elements of the steel alloys will also be considered to determine their weldability. A steel alloy with a high carbon equivalent means that it is less weldable, which also means that pre-heat and post-heat processes must be implemented to prevent cracking.
• Cooling Rates: The cooling rate of a steel alloy can also affect its state after the welding process. This specific factor is brought by the thickness of steel and the ambient temperature. High cooling rates can significantly increase the chances of cracking, which is high-carbon steel alloys must undergo slower cooling rates to prevent cracking.

Welding steel alloys can be conducted properly if these factors are considered thoroughly. For more information about the welding process, give us a call now at Sharp Welding and Crane Hire.