Quality analysis of steel bar joint of the hottest

Quality analysis of steel bar joint of steel bar butt welding machine

1 The welding strength of reinforcement is not enough

if the reinforcement quality is confirmed to be OK, the main reasons are as follows

(1) the end face of the welded reinforcement is unqualified. For example, the gap between two reinforcements is too large or too small, and there are sundries on the end face

(2) the flame adjustment is not good during the welding process, the carbonization flame is not used in the initial heating, or the flame deviates from the pressing surface, resulting in the oxidation of the end face

(3) during the welding process, the flame heating time is too long, causing a large number of carbon molecules to be burned or the heat affected zone to be too large, and the grains become thicker, thus reducing the strength of the reinforcement

(4) the heating temperature is too low or the heating time is too short, and the reinforcement center begins to pressurize before reaching the welding temperature, which is caused by the insufficient strength of some molecules in the center of the welding end face

(5) at the later stage of heating, the heater will move back in the future, causing uneven heating of the reinforcement

2. The appearance quality of the welded reinforcement is unqualified

(1) the heating temperature is low; The pressure is not enough, or the heating part is short

(2) the heating time is too long; Overpressure; Uneven heating

(3) the fixture does not clamp the reinforcement; The fixture is unloaded too early

see the following figure for the reasons and treatment methods for the unqualified quality of the welded reinforcement joint:

a. the upsetting diameter is not enough (the pier diameter is less than 1.4 times of the reinforcement); The reason is that the heating temperature is low, or the jacking screw of the fixture does not tighten the reinforcement, and the pressure is not enough

b. the length of the thick part of the pier is not enough (less than 1.2 times the diameter of the reinforcement); The reason is that the heating temperature is low, or the heating area of reinforcement is short

c. the reinforcement is not concentric; The reason is that the fixture or reinforcement is not installed concentrically, or the fixture is removed too early, or the end face of the reinforcement is tilted too much

d. axial bending of joint; The reason is that the axes of the two reinforcements are not aligned during clamping, the deformation quality of the fixture is poor, the axes of the two chucks are different or the stiffness of the fixture is not enough, and the welding fixture is disassembled too early

e. joint drooping type; The reason is that the flame is not well adjusted, the reinforcement is heated unevenly, the welding integrates the producers and consumers comprehensively, the heating lengths on both sides are different, and the high-temperature area deviates from the weld

f. offset of pressure welding surface; The reason is that the heating length on both sides of the welding is different, the high-temperature area deviates from the weld, and the pressure welding deviation is easy to occur when welding reinforcement with different diameters. Because the healthy development of the industry has carried out the top layer, it is widely used, and it is designed to require different heat for the welding of thick and fine reinforcement

g. joint burning crack; The reason is that the welding torch continues to increase pressure after it has stopped fire. When the oil level of the heating flame is less than 2/3 of the barrel depth, it should be replaced immediately; Too large, the heater swings unevenly

h. flat broken surface of joint; The reason is that the steel bar clamping gap is unqualified, the heating flame is not used correctly, the heating temperature is not enough or the heat distribution is uneven, and the top pressure is too small

3. the flame emitted by the heater is not flat, resulting in insufficient temperature and uneven heating

adjust the nozzle to be qualified with pliers or other tools

4. the pump head of the oil pump leaks oil, or the pressure rod and the plunger of the pump body leak oil, resulting in insufficient pressure

disassemble and replace the rubber sealing ring

5. the oil pump cannot be pressurized

check whether there is oil shortage in the pump body and whether there is oil leakage at all connections, or disassemble the front of the pump body and thoroughly clean all parts

6. the plunger body of the fixture is stuck with the cylinder block or the movable collet cannot be reset

remove the front of the fixture, knock out the upper fixing, clean it smooth and level, and fill it with lubricating oil. (end)