introduction

Can Decarburized Steel Plate be Welded by Electric Welding?

Abstract

Decarburization is a common phenomenon in steel fabrication, which affects the quality and performance of welded joints. This article aims to explore the possibility of welding decarburized steel plates using electric welding. By evaluating the effects of decarburization on weldability and discussing the techniques and precautions for welding decarburized steel plates, we seek to provide a comprehensive understanding of this topic.

1. Introduction

Decarburization, the loss of carbon content from the surface layer of steel, is a result of high-temperature exposure during manufacturing processes. Welding decarburized steel plates poses challenges due to the altered material properties. In this section, we will provide a brief overview of decarburization and its impact on steel weldability.

1.1 Decarburization: Causes and Effects

Decarburization occurs when carbon in steel reacts with oxygen, resulting in the formation of carbon monoxide gas. The causes of decarburization can be attributed to factors such as prolonged exposure to high temperatures, improper heat treatment, or usage of inadequate protective measures. The consequences of decarburization include reduced hardness, decreased tensile strength, and altered microstructure.

1.2 Weldability of Decarburized Steel Plates

The weldability of a decarburized steel plate depends on the extent of decarburization and its distribution. Excessive decarburization can lead to weld cracking, porosity, and other defects. Therefore, it is crucial to assess the weldability of decarburized steel plates to ensure the integrity of the welded joints.

2. Techniques for Welding Decarburized Steel Plates

To successfully weld decarburized steel plates using electric welding, certain techniques and precautions need to be considered. This section will cover four essential aspects of welding decarburized steel plates and provide detailed explanations on each.

2.1 Pre-weld Preparation

Proper pre-weld preparation is crucial for welding decarburized steel plates. This includes cleaning the surface thoroughly to remove any contaminants that could affect the quality of the weld. Additionally, preheating the plate can help reduce the risk of cracking and improve weldability.

2.2 Welding Process Selection

The choice of welding process depends on various factors, including the thickness of the plate, the desired weld quality, and the availability of equipment. Electric welding methods such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and submerged arc welding (SAW) are commonly used for welding decarburized steel plates.

2.3 Optimizing Welding Parameters

The selection of appropriate welding parameters is crucial to achieve a sound weld in decarburized steel plates. Factors such as welding current, voltage, travel speed, and electrode type should be carefully determined to minimize the risk of defects and ensure satisfactory weld quality.

2.4 Post-weld Heat Treatment

Post-weld heat treatment (PWHT) plays a significant role in relieving residual stresses and improving the mechanical properties of welded joints in decarburized steel plates. PWHT should be conducted carefully to avoid further decarburization and maintain the desired properties of the steel.

3. Conclusion

In conclusion, welding decarburized steel plates using electric welding is feasible if proper techniques and precautions are followed. Pre-weld preparation, careful selection of welding processes, optimization of welding parameters, and appropriate post-weld heat treatment are essential factors in ensuring the quality and integrity of the welded joints. Further research and experimentation are warranted to explore additional methods to minimize the negative effects of decarburization on weldability. By understanding these techniques, engineers and welders can overcome the challenges associated with welding decarburized steel plates and achieve successful welds.