1. Types of spring: There are many types of springs and various methods of classification, but none of them are decisive:
1.1 Classification according to the material used: Metal spring Steel spring Carbon steel spring Alloy steel spring Non ferrous metal springs Copper alloy spring Nickel alloy spring other Non-metallic spring Rubber spring Fluid spring Air spring Liquid spring Synthetic resin spring Laminated spring other 1.2 Classification according to shape: A. Coil springs (cylindrical, round hammer, drum, barrel) Coil tube springs B. Laminated spring C. Torsion bar D. Barrel spring E. Sliding coil spring F. Ring Spring G. Sheet Spring H. Coil Spring I. Washer type (spring washer: toothed washer, corrugated washer) J. Serrated springs, snap rings, etc
1.1. Classification according to the stress state of the material constituting the spring: A. Compression coil spring B. Tension coil spring C. Torsional coil spring D. Other coil springs E. Laminated spring F. Torsion bar G. Slide Spring H. Sheet Spring I. Coil Spring J. Spring Washer K. Wire fine work spring L. Retaining Ring M. Ring Spring 2. Function of spring: Spring is one of the mechanical elements, which is formed into an appropriate shape, making full use of the elasticity of the material and its ability to absorb energy. Therefore, as long as it is an elastic body, it can be used as a material. At the extreme, structures such as tracks and bridges can also be said to have a spring effect. However, if a spring used as a general mechanical element uses materials with a small elastic range, it will exceed the elastic limit due to small external forces or deformation, leaving residual deformation after removing the external forces, reducing the role of the spring; Therefore, elastic materials must first require greater elasticity, that is, a high elastic limit, commonly used in practical metal springs;
2、 Material selection:
Springs make extreme use of the elasticity of spring materials. Of course, materials with higher elasticity are better. However, in actual use, their materials also require physical, chemical, mechanical properties, and other conditions to choose from. Generally, the following considerations are considered:
1. Elastic limit: The elastic limit refers to the stress corresponding to the maximum force that does not remain deformed after a certain force is applied to a material and deformed, and when the force is removed, it is difficult to measure. However, materials with high relative tensile strength have a high elastic limit, and the elastic limit can be changed through heat treatment or cold processing;
2. Elastic coefficient: When a force is applied to a spring material, the stress at which a unit strain is generated is called the elastic coefficient. This value is the base of the spring design. The elastic coefficient of the spring material mainly depends on its chemical composition, which varies slightly due to heat treatment and cold processing, and can be greatly reduced when the use temperature is high;
3. Fatigue strength: Fatigue strength has a certain relationship with the tensile strength of a material, but varies due to surface condition, decarburization, cold working, and heat treatment. These conditions vary depending on the manufacturing method of the material and the manufacturing method of the spring;
4. Quench ability: In order to improve the quenching effect, large shaped springs need materials with good quenching property, which depends on the chemical composition of the material;
5. Shape and dimension: The mechanical properties of spring materials vary depending on their size, resulting in limited availability of special dimensions and shapes;
6. Heat resistance: Some springs are used at a certain degree of high temperature. Generally, the various mechanical properties of the spring material decrease as the temperature rises. Above a certain temperature, the spring properties decrease. The heat resistance varies depending on the chemical composition of the material and the manufacturing method;
7. Corrosion resistance: Sometimes springs can be used in corrosive environments, causing corrosion fatigue. The corrosion resistance mainly depends on their chemical composition, but it can also vary due to heat treatment and cold processing;
8. Electrical conductivity: Electrical appliances and communications are often used for electrical conduction, and copper composite metal spring materials such as brass, phosphorous copper, and beryllium copper can be used at this time
9. Thermal expansion: The hair springs of clocks and watches should avoid the expansion and contraction caused by temperature changes, and special materials should be used at this time;
10. Other requirements: There are also problems with crystal particle size, segregation, nonmagnetic, non-metallic inclusions, scars, heat treatment deformation, process ability, and plug resistance.
3、 General wire for springs:
1. Piano wire: (Piano wire)”Toughening treatment is carried out using piano steel wire, which is processed by strong wire drawing to give good dimensional accuracy, good surface skin, and high mechanical properties. Toughening is the process of continuously heating high carbon steel wire at a temperature above the abnormal point and cooling it in molten lead at about 500 ℃ to form a highly processable tissue.”; A. SWPA – Low tensile strength B. SWPB – High tensile strength; The tensile strength varies depending on the wire diameter, with a fine wire diameter and generally higher tensile strength; Hard Drawn Steel Wire After using hard steel wire for toughening treatment, the material and processing are not as strict as those of piano steel wire, and the high-quality ones are sometimes no less than those of piano steel wire. However, their unevenness is usually greater than that of piano steel wire, and they are widely used for springs with few repetitions and spring springs without impact load;
2.1 SWC 60C has a low carbon content
2.2 SWC 80C has a high carbon content and is widely used Stainless steel wire Stainless steel wire includes soft wire and hard wire, and spring wire is hard wire. This is made of stainless steel wire made of fire, acid pickling, and strong cold wire. It has excellent corrosion resistance, but it is also beneficial for occasions requiring heat resistance and non magnetic properties. In order to expand the tensile strength, the carbon content is increased, and the wire drawing processing degree is increased. Therefore, if the tensile strength is too high, there may be stress corrosion and susceptibility to magnetism;
3.1 SUS304
3.2 SUS316 (without magnetism)
3.3 Stainless steel materials include 202, 205, 303, 304, 308, 316, 410, 420, and 430 Generally used for springs: SUS302, SUS304, SUS316 Copper alloy elastic material – good electrical conductivity and corrosion resistance, but low heat resistance coefficient and low heat resistance;
4.1. Phosphor bronze wire (C5101W): The practical phosphor bronze for springs is a Cu alloy containing Sn3~5.5, 5.5~77~9%. To remove oxides and facilitate elongation, a small amount of P is added as a degreasing agent. After processing, the spring should be annealed at a low temperature of about 250 ℃
4.2. Brass wire (C2680W): Brass for springs is 7~3 brass with Cu 70% and Zn 30%, with low tensile strength;
4.3. White copper wire: Ni18% Zn27% Cu55% alloy, high strength, good spring characteristics, low temperature annealing at about 350 ℃ after processing; Beryllium copper: among copper alloy materials, it has the best performance, good spring elasticity, and high temperature resistance;
5. Electroplated steel wire: Depending on customer needs, the materials include SWC, SWP, and SUS Galvanized wire, tin wire, nickel wire, gold wire BATT line: (material is SUS)
6. Other wires:Copper clad wire, electric hot wire, iron wire, enameled wire.
4、 Heat Treatment (Low Temperature Annealing) – Bluing
The heat treatment of springs can improve the spring performance or supplementary performance of materials, and eliminate the stress of springs. However, due to the variety of spring materials, the heat treatment methods vary accordingly.
Heat treatment is used to improve the appearance or corrosion resistance of steel by exposing it to air, water vapor, chemicals, etc. at an appropriate temperature, forming a blue oxide film on the surface, and heating it at a low temperature of 200-400 ℃ to improve the elastic limit, fatigue limit, strength, hardness, etc. of the spring.
To increase the elastic limit, use 200-250 ℃, and to increase the fatigue limit, use 300-380 ℃. However, it is affected by the chemical composition of the steel and the degree of cold working.
5、 Changes after heat treatment of different materials:
1. SWC80C. 60C and SWPB After heat treatment of SWPA material:
1.1. Color to light brown
1.2. Angular internal contraction (increased number of turns)
1.3. Inner diameter of inner ring becomes smaller
1.4. Micro changes in processing angles
1.5. Length lengthening (free length)
1.6. The force generally becomes stronger (depending on the spring structure)
2. After heat treatment of SUS material:
2.1 The color generally does not change, and there is also a yellowing phenomenon
2.2 Angle outward expansion, reduced number of turns
2.3 The inner diameter of the flesh becomes larger
2.4 Slight changes in processing angles
2.5 The force generally decreases (varies depending on the spring structure)
2.6 Free length becomes shorter
6、 Purpose and use of anti-rust oil, degreaser, and gasoline:
1. Anti rust oil:Purpose: To prevent oxidation and rust of the spring after heat treatment; Usage: After heat treatment, it is not necessary to electroplate carbon steel wire products. The surface must be subject to rust prevention treatment. Use a spray gun to apply an appropriate amount of Spray the anti-rust oil evenly on the surface of the product;
2. Degreasing agent: Purpose: Clean the oil stain on the spring surface; Usage: The balance bar and the spring with a lot of oil stains on the surface must be cleaned with degreaser, and the cleaned spring is clean and shiny; Note: After cleaning the spring with degreasing agent, it is necessary to quickly heat treat or dry it. If it is left in the spring for too long after washing, the spring will grow instead Rust.
3. Gasoline: Purpose: Clean diesel oil and other debris on the spring surface; Usage: Mainly used for cleaning nickel plated wire springs, as cleaning nickel plated wire springs with degreasing agent can easily rust.After being cleaned with gasoline, it enhances electrical conductivity and is easy to weld. Note: After cleaning gasoline, it may catch fire when exposed to high temperatures. It is best to allow it to evaporate naturally before reheating.
7、 Heat treatment flow chart:
Explain: 1. The vibration must have a smooth cut without burrs, and the angle and length should comply with the drawing; 2. Test the temperature according to the drawing requirements, using a cursor caliper, projector, and tensile testing machine to measure;If any abnormality is found during the temperature test, it shall be reported to the superior for approval before heat treatment.
8、 Understanding of springs:
Compression spring: generates rebound force due to compression
Tension spring: The force generated by stretching is generally tight
3. Torsion spring: generates rebound force due to torsion
Hook spring: generates rebound force due to bending
9、 Explanation and terminology of spring terms:
1. Wire Diameter (abbreviated as WD), marked d, refers to the circular diameter (outer diameter) of the material used in making the spring, which is called the wire diameter, and generally refers to linear circular diameter materials;
2.”Inside Diameter” (abbreviated as “ID”), with the symbol D1. The diameter of the wire is processed and rolled into a circular shape. The diameter of the inner circumference of the circle, excluding the lines at both ends, is measured in M/M. “;
3.”Outside Diameter” is abbreviated as “OD” and marked with “D2”. As for the diameter of the circumference of the circle, including both ends of the line, OD=ID+2 WD;
4.”Diameter, abbreviated as D, is also called the average diameter. The average value (ID+OD) of the flat center diameter, inner diameter, and outer diameter is/2, which is the distance from the center point of one end of the coil through the center of the circle to the center point of the other end, in M/M.”;
5. Active coils, abbreviated as AC, marked with Na, refers to the number of effective coils of the spring, excluding the seat ring;
6. Total coils, abbreviated as T. C, marked Nt, refers to the total number of coils from one end of the spring to the other end, which is called the total number of coils. Total coils=effective coils+seat coils;
7. Seat ring: a ring in which the two parts of the compression spring contact the supporting surface and the adjacent spiral line, and there is no elastic force
Number, called seat ring;
8. Rotation direction: the direction of spring rotation, divided into left and right directions, left hand: Left hand, right hand: Right hand;
9. Free length (L) Free height (H): The length (height) of the original production when the spring is not subjected to external force, in M/M;
10. Tightness Height (Hs): The height at which the spring acts without free turns and is completely tight, known as the tightness height, in M/M;
11. Squareness: After forming a spring (generally referred to as a compression spring), its end surface usually cannot be completely planar, and its cut off points are higher, so it is placed in a slightly inclined state on the plane. The triangle formed by the spring and the plane is called squareness. Generally, when the squareness is required to be between 90 ° and 93 °, it is necessary to grind and repair the higher parts at both ends;
12. Load (P): refers to the force required by the coil spring after applying an external force to a certain length of action, called the load, in grams
(kgf), or Newton (N);
13. Finish: To achieve aesthetic purposes or to prevent rust, oxidation, or improve welding energy
A process adopted by force;
14. Pitch: The mark P is also called pitch (the distance from the center diameter of one coil to another in the compression spring);
15. Initial tension: Mark Pi in kgf;
16. Initial stress: mark Vi, unit: kgf/mm2
17. Torque, i.e. torque, mark M, unit: kgf-mm;
18. Torsion angle: mark (d), unit degree (rad);
19. Common chemical element symbols:
Zn Zn Fe O O O O Ni Ni Na Na Na C C C Au Au Pb Pb Pb
B B B Ag Ag P P I Iodine Cr Cr Li Li W W W Cu Cu Cu
Mn Mn Si Si S S S Mo Ca H H H H
10、 Roll direction recognition: there are right and left rotation
Basis: body oblique direction, upper right
Basis: upper left of body oblique direction
This method is more suitable for recognizing the winding direction of spiral compression springs
Basis: From top to bottom, starting from the cutting section, along the spiral direction, clockwise for right rotation
Basis: From top to bottom, starting from the cutting section and following the spiral direction, counterclockwise is left rotation
This method is more suitable for recognizing the winding direction of spiral compression springs
11、 Relationship between spring size and force
1. Compression spring
A. The larger the wire diameter, the stronger the force;
B. The smaller the outer diameter, the stronger the force;
C. The longer the length, the stronger the force;
D. The more turns, the less power.
2. Torsion spring
A. The thicker the wire diameter, the stronger the force;
B. The more turns, the less power;
C. The greater the angle, the stronger the force;
3. Tension spring
A. The thicker the wire diameter, the stronger the force;
B. The smaller the outer diameter, the stronger the force;
C. The more turns, the less power;
D. The longer the length, the smaller the force.
12、 Type of plating:
1. Type:
A. Nickel plating (black nickel, white nickel)
B. Chemical nickel (also known as electrolytic nickel free)
C. Gold plating (real gold, imitation gold)
D. Copper plating (red copper, brass) with a nickel base, red copper has a brighter gloss than red copper plating
E. Zinc plating (black zinc, white zinc, blue zinc)
