1. Introduction of Q690D steel for construction machinery.
Q690D is a high-strength low-alloy structural steel, which is widely used in the field of construction machinery. It has high yield strength and tensile strength, good plasticity and toughness, as well as excellent weldability and processability. This article will introduce the characteristics, applications and welding processes of Q690D steel for construction machinery in detail.
The outstanding characteristics of Q690D are high strength, good plasticity and toughness, excellent weldability and processability. It has high yield strength and tensile strength, can withstand large loads and impact forces, and has good plasticity and toughness, and is not prone to brittle fracture. In addition, the Q690D has excellent welding performance, can be joined by various welding processes, and has good processing properties, easy to cut, bend and form.
Second, the application of Q690D.
Q690D is widely used in various construction machinery fields because of its excellent mechanical properties and processing properties. The following are the main applications of Q690D in the field of construction machinery::
1.Hoisting machinery: Q690D is used to manufacture the main structural parts and parts of various cranes, tower cranes, port cranes and other equipment, such as crane arms, frames, outriggers, etc. Its high strength and excellent welding performance ensure the safety and reliability of lifting machinery.
2.Excavator: Q690D is used to manufacture the main structural parts of the excavator, such as track shoes, digging buckets, booms, etc. Its high strength and good toughness can withstand the high load and impact force during the excavation process, and improve the service life and work efficiency of the excavator.
3.Loader: Q690D is used to manufacture loader frames, buckets, booms and other components. Its excellent welding performance and processing performance make the structure of the loader more compact and lightweight, and improve the loading efficiency.
4.Concrete machinery: Q690D is used to manufacture supporting structural parts and mixing blades and other components of concrete batching plants, concrete pump trucks and other equipment. Its high strength and good toughness can withstand the impact and wear of concrete on the equipment, and prolong the service life of the equipment.
5.Other machinery: Q690D is also widely used in bulldozers, rollers, graders and other construction machinery fields, as the main material for various structural parts and parts.
3. Welding process of Q690D.
Since the Q690D has good welding performance, it can be joined by a variety of welding processes. The following are the commonly used Q690D welding processes:
1.Manual arc welding: Welding with low-hydrogen electrodes, such as J507 or J607 electrodes. Preheating should be carried out before welding, the preheating temperature is 150 250, and the interlayer temperature should not be lower than the preheating temperature during the welding process. After welding, hydrogen dehydration treatment should be carried out, that is, it should be kept at about 200 for more than 2 hours.
2.Submerged arc welding: Low hydrogen submerged arc welding wire is used for welding, such as H13Mn2TIA or H13Mn2MoA welding wire. Preheating should be carried out before welding, the preheating temperature is 150 250, and the interlayer temperature should not be lower than the preheating temperature during the welding process. After welding, hydrogen dehydration treatment should be carried out, that is, it should be kept at about 200 for more than 2 hours.
3.Gas shielded welding: CO2 gas shielded welding or mixed gas shielded welding (AR+CO2) is used, and low-hydrogen welding wire such as H13Mn2MOA or H13Mn2TIA is used for welding. Preheating should be carried out before welding, the preheating temperature is 150 250, and the interlayer temperature should not be lower than the preheating temperature during the welding process. After welding, hydrogen dehydration treatment should be carried out, that is, it should be kept at about 200 for more than 2 hours.
4.Resistance welding: Spot welding or projection welding processes are used for connection. Special electrodes are used for spot welding, and appropriate bumps are selected as connection points for projection welding. When welding, the appropriate current and electrode pressure should be selected according to the actual situation.
5.Brazing: Brazing joints with silver or brass filler metals. First of all, preheat the Q690D steel plate to.