How welding hardened steel have more strength than normal steel?

March 8, 2021

Emmanuel

I am a professional welder with over 10 years of experience. Welding is my first love and writing is my second. I enjoy writing on welding topics.

Applying any process practically means knowing beforehand about its pros and cons. The same is the case with the process of welding hardened steel. Before using it to any material, make sure it has no adverse effects on it. It would help if you did not compromise with the end product. During welding, one of the most probable questions that arise is regarding welding hardened steel.

As the name As the name suggests, welding hardened steel is a form of carbon steel that is relatively stronger than standard steel. It is due to the presence of higher carbon. Welders develop hardened steel by making it go through several heating cycles to make them stainless. This makes the steel tough and resilient. This also makes the process of welding quite difficult on hardened steel.

Welding hardened steel is quite a tough job, as it needs extra attention. We use a heath that can be harmful to our end product during the welding of hardened steel. If welders do not use the right techniques for the heating and cooling steel, the resulting joint can become fragile. To avoid weak joints, use suitable heating techniques on the metal before welding. If you heat the metal properly and put some weight on the metal joints, you can easily weld hardened steel. Welding hardened steel is quite a tough job, as it needs extra attention. We use a heath that can be harmful to our end product during the welding of hardened steel. If welders do not use the right techniques for the heating and cooling steel, the resulting joint can become fragile. To avoid weak joints, use suitable heating techniques on the metal before welding. If you heat the metal properly and put some weight on the metal joints, you can easily weld hardened steel.

welding hardened steel

What do you mean by the Hardening of materials in welding?

In the field of metallurgy, the Hardening of materials means increasing their hardness. Metals are made more challenging by applying some hardening techniques to them. This increases their surface hardness and makes them more resilient to beating. Due to this, it is difficult to deform hard metals. That’s why welders mostly use hardened steel for the construction of tools and machines.

Let’s learn more about the various techniques of hardening metals

There are approximately five techniques by which the welders harden steel and other metals.

  • The Hardening method where welders use small-sized grains to fill in the surface gaps in metals. Welders call it the Grain boundary method of Hardening. In this hardening metal technique, welders use petite size grains to increase the possibility of dislocations on the metal surface. If we use grains of smaller size, it will make the metal harder. However, if welders use grains of size smaller than microns, the process becomes irrelevant. Instead of Hardening, the metal becomes softer. Therefore, while applying the grain boundary technique for metal hardening, always ensure that the grain size is not too small.
  • Another technique of hardening metals is by applying strain on them. This method goes by the name Work or strain hardening. This technique involves the use of pressure on the metal surfaces to reach beyond their yield points. When the metals get past their yield points, they become permanently deformed. This is perfect for ductile metals. This deformation is plastic deformation. Due to this, the surface of metal experiences new dislocations with increased solidity. This results in the cessation of any more dislocation since both dislocations cancel each other out. This makes the metal more problematic than before.
  • This method of hardening metals is called Hardening by a reliable solution. In this method, the metal that needs Hardening is made to form a reliable solution by adding some alloying element. It results in a relative difference in the size of the elements present inside the solution. This size difference decreases the amount of dislocation in the metal. Due to fewer dislocations, the metal becomes rigid and resists breaking. There is no formation of any precipitate in this technique of metal hardening.
  • The method of Hardening by precipitation involves the process of forming a reliable solution. It is the same as creating a solid solution in the above technique of metal hardening. Welders use an alloying element and mix it with the metal that needs Hardening. However, the significant difference between the two is the formation of a precipitate. In the above technique, no deposit is formed by the ions of the alloying element. Whereas in this method, the particles of matrix metal form a precipitate. It results in the resistance of dislocations so that the metal surface remains strong and smooth.
  • Welders can also achieve hardened metals by tempering them. It is mainly applicable to the Hardening of steel. This method involves heating the steel at high temperatures. Increase the temperature until the steel changes its phase of iron. Or in other words, steel alters its crystal structure. The ferrite phase of iron becomes the austenite phase after the heating process. In this phase, steel easily dissolves more amount of carbon. After carbon dissolves in the steel, the steel undergoes quenching or tempering. Hence, the steel hardens.

How can we avoid the weakening of steel after the process of welding?

Welders often complain that after the process of welding, steel becomes weak. To avoid this, welders use heating techniques after welding is done. This ensures that the weld joints remain healthy. Due to all the heating during the process of welding, the affected areas lose their hardness. This makes them prone to breaking and cracking when under intense pressure. But due to the heating techniques, the hardness of steel remains intact.

You can use all these benefits of heat treatment, but what’s crucial is to do it properly. After completion of the welding process, heating the weld metal ensures that the steel does not lose its strength. After heating techniques, the steel becomes rich in several properties. It becomes more robust, more challenging, and more stringent. It was heating the steel after welding increases its tensile strength and removes any stress.

All the available heating techniques depend on various characteristics like the structure of weld, type of metal, chemical composition, etc. Therefore, before applying any of them, make sure it’s the right one.

Where do we use hardened steel in practical applications?

Several industries require the use of hardened steel for practical purposes. It is better than soft steel because of its increased tensile strength. After heating the steel, it becomes relatively more demanding and more challenging than standard steel. Therefore, it is advisable to heat the steel after it undergoes the welding process.

Tools and equipment that we use for cutting machines and their parts use hardened steel. Welders need tools that are relatively harder than the parts that need cutting. If their hardness is the same, difficulties will arise. Similarly, hardened steel is useful for making blades and knives, which require efficient cutting.

In machines, the ball bearings also need to have significant tensile strength. It makes them resistant to intense pressure. If they are soft, the device will break easily under stress. Therefore, we use hardened steel for the production of bearings in machines. Due to their higher strength, defense industries use them to develop bulletproof jackets and armors. In the case of mining, devices also require the use of hardened steel.

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