How To Do Weld Cracks Repairing of Press Body

Weld Crack Repair Welding Process and Key Points

This article is to introduce the solution of weld cracks happens on press machine steel-welded body.

1. Pre-Welding Preparation

1.1  Defect Inspection and Crack Arrest Treatment

First, confirm the complete propagation path. Drill φ5~φ10mm crack arrest holes at both ends of the crack, with the hole depth slightly exceeding the crack depth, to prevent the crack from further extending during the repair welding process.

1.2  Groove Preparation and Cleaning

Use an angle grinder to grind the cracked area into a V-shaped or U-shaped groove without sharp corners. Thoroughly remove oil, rust and oxide scales within 20mm around the groove to expose the pure base metal, so as to avoid defects such as pores and incomplete fusion caused by impurities.

1.3  Process Matching and Preheating

CO2 shielded welding, 500A welding machine, 1.2mm welding wire. Preheat to 50℃, to reduce welding stress and lower the risk of cold cracks.

2. Formal Repair Welding Operation

2.1 Backing Welding

Adopt low current and low welding speed to complete the root backing welding, ensure full penetration. Remove the slag after welding and inspect the root to eliminate hidden internal defects.

2.2 Layered Filling

Do not adopt one-step full-length welding. Fill the groove alternately layer by layer along both sides of the groove. Keep the electrode angle at 75°~80°, to ensure sufficient fusion between each weld pass and the base metal as well as adjacent weld passes and control the interlayer temperature within a reasonable range.

2.3 Stress Control

Adopt distributed welding and short-segment welding to avoid local heat concentration. Gently tap the weld bead after welding a short section to release stress and reduce residual stress accumulation.

3. Improvement

If possible, to add an extra plate and weld it on the body.