Does the forging process cause quality problems for forgings?
2022-11-04
Forgings quality problems are caused by many reasons, through the macro and micro analysis of the forgings, sometimes also carry out simulation test, so as to find out whether the cause of quality problems is the forging process itself or other influencing factors (such as raw materials, heat treatment, table and treatment or the test itself error, etc.); Only after careful research and analysis can conclusions be drawn whether the forging process is not reasonable and imperfect or the process discipline is not strict and the process is not executed seriously. What is known about the forging process?
1. Upsetting: Upsetting is the operation process of forging the original billet along the axial direction to reduce its height and increase its cross section. This process is often used to forge gear blanks and their disc-shaped forgings. Upsetting can be divided into two kinds: total upsetting and partial forging.
In order to prevent longitudinal bending when the pier is thick, the ratio of height to diameter of the cylinder billet should not exceed 2.5-3, and the billet end face should be flat and perpendicular to the axis line before upsetting. When upsetting, the billet is constantly turned around the axis line and the billet must be corrected immediately if it bends.
2. Drawing length: Drawing length is a forging process that increases the length of the blank and decreases the section. It is usually used to produce the blank of shaft parts, such as the spindle and connecting rod of the lathe.
The pressing amount of each hammer stroke should be less than the allowable value of billet plasticity and avoid folding, so the ratio of width to height of forging after each compression should be less than 2-2.5. b/h < 2-2.5, otherwise turn 90 degrees, prone to bending and folding when forging.
3. Punching: The forging process of punching out through holes or through holes on the blank with the punch.
4. Bending: forging process to bend the billet into a certain Angle or shape.
5. Torsion: the forging process that makes one part of the blank rotate at a certain Angle relative to the other part.
6. Cutting: forging process of dividing billet or cutting out material head.
The die movement of forging equipment is inconsistent with the degree of freedom. According to the deformation restriction characteristics of the bottom dead point, forging equipment can be divided into the following four forms:
1, limit forging force form: oil pressure directly drive slider oil press.
2. Quasi stroke restriction mode: hydraulic drive crank-connecting rod mechanism hydraulic press.
3, stroke limitation mode: crank, connecting rod and wedge mechanism to drive the slide mechanical press.
4, energy limitation mode: the use of spiral mechanism of spiral and friction press.
In order to obtain high accuracy, attention should be paid to prevent overload at the bottom dead point, control speed and mold position. Because these will have an impact on forging tolerance, shape accuracy and forging die life. In addition, in order to maintain the accuracy, attention should also be paid to adjusting the clearance of the slide guide rail, ensuring the stiffness, adjusting the bottom dead point and using the auxiliary transmission device and other measures.
Forgings quality problems are caused by many reasons, through the macro and micro analysis of the forgings, sometimes also carry out simulation test, so as to find out whether the cause of quality problems is the forging process itself or other influencing factors (such as raw materials, heat treatment, table and treatment or the test itself error, etc.); Only after careful research and analysis can conclusions be drawn whether the forging process is not reasonable and imperfect or the process discipline is not strict and the process is not executed seriously.
Since the quality problems of forging include appearance quality and internal quality problems, and various problems may be related to each other, so the focus of the analysis should be comprehensive, to consider the forging defects and mechanical properties of the connection, the mutual influence of the forging defects themselves.
1. Upsetting: Upsetting is the operation process of forging the original billet along the axial direction to reduce its height and increase its cross section. This process is often used to forge gear blanks and their disc-shaped forgings. Upsetting can be divided into two kinds: total upsetting and partial forging.
In order to prevent longitudinal bending when the pier is thick, the ratio of height to diameter of the cylinder billet should not exceed 2.5-3, and the billet end face should be flat and perpendicular to the axis line before upsetting. When upsetting, the billet is constantly turned around the axis line and the billet must be corrected immediately if it bends.
2. Drawing length: Drawing length is a forging process that increases the length of the blank and decreases the section. It is usually used to produce the blank of shaft parts, such as the spindle and connecting rod of the lathe.
The pressing amount of each hammer stroke should be less than the allowable value of billet plasticity and avoid folding, so the ratio of width to height of forging after each compression should be less than 2-2.5. b/h < 2-2.5, otherwise turn 90 degrees, prone to bending and folding when forging.
3. Punching: The forging process of punching out through holes or through holes on the blank with the punch.
4. Bending: forging process to bend the billet into a certain Angle or shape.
5. Torsion: the forging process that makes one part of the blank rotate at a certain Angle relative to the other part.
6. Cutting: forging process of dividing billet or cutting out material head.
The die movement of forging equipment is inconsistent with the degree of freedom. According to the deformation restriction characteristics of the bottom dead point, forging equipment can be divided into the following four forms:
1, limit forging force form: oil pressure directly drive slider oil press.
2. Quasi stroke restriction mode: hydraulic drive crank-connecting rod mechanism hydraulic press.
3, stroke limitation mode: crank, connecting rod and wedge mechanism to drive the slide mechanical press.
4, energy limitation mode: the use of spiral mechanism of spiral and friction press.
In order to obtain high accuracy, attention should be paid to prevent overload at the bottom dead point, control speed and mold position. Because these will have an impact on forging tolerance, shape accuracy and forging die life. In addition, in order to maintain the accuracy, attention should also be paid to adjusting the clearance of the slide guide rail, ensuring the stiffness, adjusting the bottom dead point and using the auxiliary transmission device and other measures.
Forgings quality problems are caused by many reasons, through the macro and micro analysis of the forgings, sometimes also carry out simulation test, so as to find out whether the cause of quality problems is the forging process itself or other influencing factors (such as raw materials, heat treatment, table and treatment or the test itself error, etc.); Only after careful research and analysis can conclusions be drawn whether the forging process is not reasonable and imperfect or the process discipline is not strict and the process is not executed seriously.
Since the quality problems of forging include appearance quality and internal quality problems, and various problems may be related to each other, so the focus of the analysis should be comprehensive, to consider the forging defects and mechanical properties of the connection, the mutual influence of the forging defects themselves.
this is forging production machine of tongxin precision forging company:
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