CN210948923U - Structure for improving fatigue strength resistance of steel piston weld joint - Google Patents
Structure for improving fatigue strength resistance of steel piston weld joint Download PDFInfo
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- CN210948923U CN210948923U CN201921583247.5U CN201921583247U CN210948923U CN 210948923 U CN210948923 U CN 210948923U CN 201921583247 U CN201921583247 U CN 201921583247U CN 210948923 U CN210948923 U CN 210948923U
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Abstract
The utility model discloses a structure for improving fatigue strength of steel piston welding seam, including the piston body, be provided with interior cooling oil pocket A on the piston body, the outer wall of interior cooling oil pocket A is provided with the combustion chamber ring, the outside of combustion chamber ring is provided with the larynx mouth, the top that the piston body corresponds interior cooling oil pocket A is provided with first area inclination top welding seam, the side position that the piston body corresponds interior cooling oil pocket A is provided with area inclination combustion chamber welding seam, still includes right side piston body, be provided with interior cooling oil pocket B on the piston body of right side; because of the restriction of piston structure, high compression and weight, the welding surface area of the oblique welding seam is larger than that of the straight welding seam under the condition of unchanged piston wall thickness; the inclined welding seam has component force in the axial direction and the radial direction of the piston, and the stress of the welding seam reaches the best by adjusting the inclination angle theta of the welding seam; under the same condition, the fatigue resistance of the oblique weld of the steel piston is superior to that of the straight weld.
Description
Technical Field
The utility model belongs to the technical field of well heavy diesel engine, concretely relates to improve structure of steel piston welding seam fatigue strength.
Background
The patent of the utility model discloses a heavy diesel engine field in being applicable to. Steel pistons have been used for decades in the field of medium and heavy duty internal combustion engines where the maximum burst pressure in the cylinder can reach 25 MPa. The aluminum piston material cannot bear such high explosion pressure in the aspects of thermal load and mechanical load, and the fatigue life of the aluminum piston material cannot meet the requirement of durability, so that the steel piston replaces the aluminum piston under the condition of high explosion pressure; the steel piston comprises an integral steel piston, a hinged steel top aluminum skirt piston and a welded steel piston, wherein the welded steel piston is of an integral structure formed by welding a top forged steel material and the skirt part, and has the advantages of good cooling efficiency, high integral rigidity, particularly high rigidity of a ring bank area, and good reliability due to the fact that a cooling oil passage is closed; because the working temperature of the steel piston is higher, the highest temperature of the edge of the combustion chamber reaches more than 450 ℃, and the excessively high working temperature easily causes the surface of the material at the edge of the combustion chamber to be oxidized under the action of high-temperature fuel gas, so that a fatigue source is generated to cause the piston to crack. To welded steel piston, its welding seam equally has the risk of taking place fatigue fracture, the utility model relates to a welded steel piston field aims at improving the fatigue resistance ability of the welding seam of steel piston, effectively reduces the risk that fatigue fracture takes place for the steel piston welding seam.
At present, the mainstream welding modes of the steel piston include three modes of friction welding, laser welding and electron beam welding. Friction welding is a solid-phase forging welding technique, and although welding defects and embrittlement phenomena related to melting and solidification do not exist in a welding seam, the strength of the welding seam can reach or even exceed the strength of a base metal, the friction welding has three defects due to the limitation of a welding mode: the welding tool is only suitable for welding annular and coaxial weldments; 2. welding burrs inside the oil cavity cannot be removed, the cooling effect of the cold oil cavity in the piston is influenced, and stress concentration is easily caused by the welding burrs; 3. workpiece deformation and axial dimensional instability can result from the application of loads during welding. Laser welding and electron beam welding belong to high-energy beam welding, and the depth-to-width ratio of laser welding is generally 10: within 1, the aspect ratio of electron beam welding is typically 20: 1, although high energy beam welding can produce a non-concentric combustion chamber structure compared to friction welding, when welding steel pistons, there are still dense porosity, lack of penetration, cracks, etc. at the weld joint, which can reduce the fatigue resistance of the weld joint.
At present, straight welding seams are used for welding seams on the top of the piston by electron beam welding and laser welding. The welding form of the straight welding seam is convenient for manufacturing, processing and positioning, but has the following defects:
(1) the welding surface area is small by adopting a straight welding line;
(2) because the welding seam on the top of the piston is acted by pressure (or pulling force) and shearing force, and the straight welding seam has no component in the radial direction of the piston, under the comprehensive stress condition of the work of the piston, the straight welding seam is not well stressed and is more easy to generate fatigue cracking;
(3) due to the structural limitation of the piston, the tensile test bar is difficult to take from the piston, and only the test bar can be taken from a welding sample piece for analog judgment.
SUMMERY OF THE UTILITY MODEL
An object of the utility model is to provide an improve steel piston welding seam fatigue strength's structure to solve the problem that proposes in the above-mentioned background art.
In order to achieve the above object, the utility model provides a following technical scheme: a structure for improving the fatigue resistance of a steel piston weld joint comprises a piston body, wherein an inner cooling oil cavity A is arranged on the piston body, the outer wall of the inner cooling oil cavity A is provided with a combustion chamber ring, the outer side of the combustion chamber ring is provided with a throat, the piston body is provided with a first top welding line with an inclination angle corresponding to the top of the internal cooling oil cavity A, the piston body is provided with a combustion chamber welding line with an inclination angle corresponding to the side of the internal cooling oil cavity A, the piston further comprises a right piston body, the right piston body is provided with an inner cooling oil cavity B, the outer side of the inner cooling oil cavity B is provided with a right throat, the piston further comprises an outer ring, a right piston body is arranged below the inner cooling oil cavity B on the outer ring, and a second top welding seam with an inclination angle is arranged on the outer ring corresponding to the upper part of the internal cooling oil cavity B, and a skirt welding seam with an inclination angle is arranged on the side of the internal cooling oil cavity B.
Preferably, still include straight welding seam piston body, the left side top of straight welding seam piston body is provided with the straight welding seam in first top, and the left side of straight welding seam piston body is provided with the combustion chamber welding seam, the right side top of straight welding seam piston body is provided with the straight welding seam in second top, the right side of straight welding seam piston body is provided with the skirt portion welding seam.
Preferably, the first angled top weld, the angled combustor weld, the second angled top weld, and the angled skirt weld have an angle of inclination relative to the existing weld.
Preferably, the first top straight welding seam, the combustion chamber welding seam, the second top straight welding seam, the skirt welding seam, the first inclined angle top welding seam, the inclined angle combustion chamber welding seam, the second inclined angle top welding seam and the inclined angle skirt welding seam are all welded by electron beams or laser.
Preferably, the piston body and the right piston body are made of high-pressure-resistant and high-temperature-resistant materials, and the materials are materials in the prior art.
Compared with the prior art, the beneficial effects of the utility model are that: the utility model has scientific and reasonable structure, safe and convenient use, and adopts the inclined weld seam with the welding surface area larger than the straight weld seam under the condition of unchanged piston wall thickness due to the restriction of piston structure, high compression and weight; the inclined welding seam has component force in the axial direction and the radial direction of the piston, and the stress of the welding seam reaches the best by adjusting the inclination angle theta of the welding seam; under the same condition, the fatigue resistance of the steel piston oblique welding seam is superior to that of a straight welding seam; the welding seam form of the steel piston high-energy beam welding is divided into two types: two welding seams at the top part and the combustion chamber part and two welding seams at the top part and the ring groove part; when the structure of the welding seam of the top part and the combustion chamber part is used, the form of adding a process joint is adopted, and the convenience in processing and manufacturing is ensured; when the structure of the welding seam at the top part and the ring groove part is used, the processing technology is the same as that of a straight welding seam structure, but the welding area is increased, and the fatigue resistance of the welding seam is improved.
Drawings
FIG. 1 is a schematic structural view of a straight weld joint combination of the present invention;
FIG. 2 is a schematic structural view of a top oblique weld of the present invention;
FIG. 3 is a first diagram of the analysis of the dip angle of the top fillet weld of the present invention;
FIG. 4 is a second diagram of the analysis of the dip angle of the top fillet weld of the present invention;
FIG. 5 is a graph of the stress analysis of the welding line by the inclination angle θ of the present invention;
in the figure: 1-a first top straight welding seam, 2-a combustion chamber welding seam, 3-a second top straight welding seam, 4-a skirt welding seam, 5-a first inclined angle top welding seam, 6-an inclined angle combustion chamber welding seam, 7-a second inclined angle top welding seam, 8-an inclined angle skirt welding seam, 11-a piston body, 12-a combustion chamber ring, 13-an inner cooling oil cavity A, 14-a throat, 21-a right side piston body, 22-an inner cooling oil cavity B, 23-an outer circular ring and 24-a right side throat.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 1-5, the present invention provides a structural solution for improving the fatigue strength of the weld joint of a steel piston: a structure for improving the fatigue resistance of a steel piston welding seam comprises a piston body 11, wherein an inner cooling oil cavity A13 is arranged on the piston body 11, a combustion chamber ring 12 is arranged on the outer wall of the inner cooling oil cavity A13, a throat 14 is arranged on the outer side of the combustion chamber ring 12, a first inclined top welding seam 5 is arranged on the top of the piston body 11 corresponding to an inner cooling oil cavity A13, an inclined combustion chamber welding seam 6 is arranged on the side position of the piston body 11 corresponding to an inner cooling oil cavity A13, the structure also comprises a right piston body 21, an inner cooling oil cavity B22 is arranged on the right piston body 21, a right throat 24 is arranged on the outer side of the inner cooling oil cavity B22, the structure also comprises an outer ring 23, and a right piston body 21 is arranged below the inner cooling oil cavity B22 on the, and a second top welding seam 7 with an inclination angle is arranged on the outer ring 23 corresponding to the upper part of the internal cooling oil cavity B22, and a skirt welding seam 8 with an inclination angle is arranged on the side of the internal cooling oil cavity B22.
In this embodiment, preferred, still include straight welding seam piston body, the left side top of straight welding seam piston body is provided with first top straight weld 1, and the left side of straight welding seam piston body is provided with combustion chamber welding seam 2, and the right side top of straight welding seam piston body is provided with second top straight weld 3, and the right side of straight welding seam piston body is provided with skirt portion welding seam 4.
In this embodiment, the first angled top weld 5, the angled combustion chamber weld 6, the second angled top weld 7, and the angled skirt weld 8 are preferably angled relative to the existing welds.
In the embodiment, preferably, the first top straight weld 1, the combustion chamber weld 2, the second top straight weld 3, the skirt weld 4, the first dip top weld 5, the dip combustion chamber weld 6, the second dip top weld 7 and the dip skirt weld 8 are all welded by electron beam welding or laser welding.
In this embodiment, preferably, the piston body 11 and the right piston body 21 are made of high pressure and high temperature resistant materials, and the materials are materials in the prior art.
The utility model discloses a theory of operation: in the utility model shown in fig. 3, the phi mark refers to the outer diameter of the combustion chamber ring; the mark theta 1 refers to the top weld dip; the theta 2 mark refers to the welding seam inclination angle of the combustion chamber; the t mark refers to a blank process joint; the L mark refers to the oblique length of the welding seam; the B notation refers to the weld thickness.
In fig. 4 of the present invention, the mark θ 1 indicates the top weld dip; the mark theta 2 refers to the inclination angle of the excircle weld joint; the L mark refers to the oblique length of the welding seam; the B notation refers to the weld thickness.
Fig. 3 shows a structure and a manufacturing method for improving fatigue resistance of a steel piston weld joint, wherein finish machining is finished before welding of an inner cooling oil cavity A13 on a piston body 11, finish machining is also carried out on an inner cooling oil cavity A13 on a combustion chamber ring 12, and the piston body 11 and the combustion chamber ring 12 are combined to form a finished and closed inner cooling oil cavity A13.
The first top weld 5 with the inclination angle θ 1 on the piston body 11 has a section length of L and a weld thickness of B, as can be seen from fig. 3, where B is Lcos θ 1, that is, the welding surface area of the oblique weld is greater than that of the straight weld; under the same welding condition, the fatigue resistance of the oblique welding seam at the top of the steel piston is higher than that of the straight welding seam.
According to the No. 7.1.1 of GB50017 Steel Structure design Specification, in butt joints and T-shaped joints, the strength of the butt joint is not calculated when an included angle theta between the welding line and an acting force is consistent with tan theta and is less than or equal to 1.5, and the stress of the welding line can be optimized when high-energy beam welding is met by adjusting the top welding line inclination angle theta 1 and the combustion chamber welding line inclination angle theta 2, so that the fatigue resistance of the welding line of a steel piston is improved, and the fatigue resistance of an oblique welding line is superior to that of a straight welding line.
Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.
Claims (5)
1. The utility model provides an improve steel piston welding seam fatigue resistance's structure, includes piston body (11), its characterized in that: the piston comprises a piston body (11), an inner cooling oil cavity A (13) is arranged on the piston body (11), a combustion chamber ring (12) is arranged on the outer wall of the inner cooling oil cavity A (13), a throat (14) is arranged on the outer side of the combustion chamber ring (12), a first top welding seam (5) with an inclination angle is arranged at the top of the piston body (11) corresponding to the inner cooling oil cavity A (13), a combustion chamber welding seam (6) with an inclination angle is arranged at the side position of the piston body (11) corresponding to the inner cooling oil cavity A (13), a right piston body (21) is further included, an inner cooling oil cavity B (22) is arranged on the right piston body (21), a right throat (24) is arranged on the outer side of the inner cooling oil cavity B (22), an outer ring (23) is further included, a right piston body (21) is arranged below the inner cooling oil cavity B (22) on the outer ring (23), and a second top welding seam (7) with an inclination angle is arranged above the inner cooling, and a skirt welding seam (8) with an inclination angle is arranged on the side of the internal cooling oil cavity B (22).
2. The structure for improving the fatigue strength of the weld joint of the steel piston as recited in claim 1, wherein: still include straight welding seam piston body, the left side top of straight welding seam piston body is provided with first top straight weld (1), and the left side of straight welding seam piston body is provided with combustion chamber welding seam (2), the right side top of straight welding seam piston body is provided with second top straight weld (3), the right side of straight welding seam piston body is provided with skirt section welding seam (4).
3. The structure for improving the fatigue strength of the weld joint of the steel piston as recited in claim 1, wherein: compared with the existing welding seams, the first top welding seam (5) with the inclination angle, the welding seam (6) with the inclination angle combustion chamber, the second top welding seam (7) with the inclination angle and the welding seam (8) with the inclination angle skirt part have certain inclination angles.
4. The structure for improving the fatigue strength of the weld joint of the steel piston as recited in claim 2, wherein: the first top straight welding seam (1), the combustion chamber welding seam (2), the second top straight welding seam (3), the skirt welding seam (4), the first inclined angle top welding seam (5), the inclined angle combustion chamber welding seam (6), the second inclined angle top welding seam (7) and the inclined angle skirt welding seam (8) are all welded by electron beams or laser.
5. The structure for improving the fatigue strength of the weld joint of the steel piston as recited in claim 1, wherein: piston body (11) and right side piston body (21) are high pressure resistant high temperature resistant material, and the material is among the prior art.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921583247.5U CN210948923U (en) | 2019-09-23 | 2019-09-23 | Structure for improving fatigue strength resistance of steel piston weld joint |
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| CN201921583247.5U CN210948923U (en) | 2019-09-23 | 2019-09-23 | Structure for improving fatigue strength resistance of steel piston weld joint |
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| CN210948923U true CN210948923U (en) | 2020-07-07 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112548506A (en) * | 2020-12-11 | 2021-03-26 | 湖南江滨机器（集团）有限责任公司 | Remanufacturing method of steel piston |
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2019
- 2019-09-23 CN CN201921583247.5U patent/CN210948923U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112548506A (en) * | 2020-12-11 | 2021-03-26 | 湖南江滨机器（集团）有限责任公司 | Remanufacturing method of steel piston |
| CN112548506B (en) * | 2020-12-11 | 2022-07-05 | 湖南江滨机器（集团）有限责任公司 | Remanufacturing method of steel piston |
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