What happens to a bolt when you weld on it?

Date Posted:

May 24, 2021

Post Author:

Marsh Fasteners

Last Updated on January 12, 2022 by Marsh Fasteners

Although welding a bolt is not an ideal solution to many engineering issues, it may sometimes be necessary. With the different types of bolts available and the various projects they are used for, it is essential to know if welding a bolt will weaken it. It should be noted that certain bolts’ grades and size can make it impossible or unsafe to weld them.

Welding on a heat-treated bolt will weaken it because it would heat the bolt beyond its tempering point. When considering welding a bolt in any situation, you will need to know the material properties you are dealing with beforehand. When heat is applied to a pre-heated bolt, its strength will be altered. Moreover, when a tempered bolt is subjected to heat in an uncontrolled environment, the outcome is uncertain.

Overheating the steel bolt

Overheating a hardened steel bolt could soften it if the temperature used is too high or if the bolt is exposed to the heat for a long time. If you weld a Grade 8 bolt, you could soften it to the strength that Grade 5 possesses. No matter how little heat you use, heating the bolt in uncontrolled conditions will weaken it.

Can you weld a high-strength anchoring bolt or fastener?

When dealing with bolts, you will come across different situations that call for various bolt strengths. The general rule of thumb is that the welding of high-strength bolts is not permitted nor advised. During the manufacturing of these bolts, a specific heating process is used to reach each bolt’s strength. When being reheated, this compromises the structure of the bolt, hence why it is not recommended.

Why are high-strength bolts heat-treated?

High-strength bolts are heat-treated to handle the intense tension and shear force caused by specific loads. Bolt heat-treatment processes differ to achieve specific outcomes. Some heat-treatment processes harden the bolt while others soften it. So, if you get two bolts that state their exact compositions (hardened or softened), you can determine the welding outcome for the bolts.

Even if your bolt is weldable, the application of the bolt welding procedure matters a great deal. Always consult an expert near you, especially when dealing with a safety-sensitive project. If you have any questions or need further information on this topic, turn to Marsh Fasteners for the best answers.