Selection of welding consumables for heat treatment of structural steel

Main products and common welding consumables

Our main products involve metallurgical machinery, port machinery, lifting machinery, bulk material handling machinery and wind power equipment, large marine crankshafts, tunnel boring equipment, low-pressure steam turbine cylinders and generator equipment. The commonly used welding consumables in the manufacturing process of the product are shown in the attached table, Figure 1, Figure 2.

Welding material application case and solution

In actual production, the main difficult problem we encountered about welding consumables is: the selection of materials for special requirements of materials. The difficulty in selecting materials is after annealing or normalizing, the impact energy of weld metal and heat affected zone cannot meet the requirements of low temperature impact. .

(1) Brief description of the project: Ring welding flange with dimensions of 160mm×φ4000mm/φ3650mm. Our company produces more than 70 pieces, and the flange material is Q345-E. After flange welding, it should be normalized and processed after normalizing. When the sample is taken for mechanical property analysis, the shock absorption energy at -40 °C should be ≥16J.

(2) Problems: More than 10 kinds of welding wires such as ER50-6, ER50-G, TWE-711, TWE-711Ni, HS09MnDR and H10Mn2 were selected for testing. The specimens were sampled and tested after normalizing, and the energy absorbed by -40 °C shock absorption Unable to meet the requirements.

(3) The solution is to test the HS09MnNiDR welding wire (Ha welding station). After the test piece is normalized, the sample is tested and the absorption energy at -40 °C meets the product requirements. Finally, the wire was selected for product manufacturing. But the wire is expensive and costs more than five times the budget.

(4) Test summary As shown in Fig. 3, after a series of welding material tests, we found that the temperature of the heat treatment directly affects the impact properties of the welding material. The higher the heat treatment temperature, the lower the impact value.

Expectations and suggestions for the future development and development of welding consumables

(1) Experimental study on different heat treatment conditions of welding consumables Most structural products require annealing and stress relief after welding, and some need to be tempered or normalized. It is hoped that the welding material manufacturers should also carry out tests under different heat treatment conditions. Research to meet the needs of different structures.

(2) When the shortage of special welding consumables involves high-strength steel welding such as Weldox960, only imported high-strength steel welding consumables can be purchased, which has high cost and long supply period. It is hoped that domestic welding consumables will be more committed to the research of some high-strength steel welding consumables and develop mature industries. In addition, many domestic researches on heat-resistant steel wire, low-temperature steel wire, atmospheric corrosion resistant steel wire and stainless steel wire are carried out.