Use and performance of screws and floor springs

1. Screw
1. Wood screws

2. Special performance nails

(1) Product series ABC class-high-speed screwing in wood screws

Fine category——–Special nails for narrow plates

Adjustment type——Special nails for grid shed

Type C———Special nails for Polaroid board

GA——-mini wood screws

Type B————Special wall nails

(2) Product features

A. Extra-deep cross groove or square groove is convenient for screwing in electric tools, which can double the work efficiency.

B. Scraping ribs under the head to scrape out countersinks for easy head burying.

C. The rod is knurled for reaming, with serrated threads for quick screwing.

D. The burr reaming blade makes the wood less easy to crack and screw in more easily.

E, Special adjustments use left-hand thread to adjust the gap, easy and free.

F. Special deep hole screws with decorative plastic cover, fast decoration construction and beautiful appearance.

G. Imported steel material is used, after carburizing heat treatment, it has high strength, large torsion force and stronger connection.

(3) Classification:

Micro wood screw with screwdriver 1.9—-refers to screw thickness 2.5—–refers to length, the price per box

From the perspective of sales, Class B is not widely used. Small-sized ABC is widely used, has a large sales volume, moderate price, and high quality.

1. Various floor nails

(1) Floor nails are made of galvanized iron.

The specifications are 50mm 2″ retail price 6.80 yuan per kilogram; 65mm-2/2″ retail price 6.24 yuan per kilogram.

It can use 4-5m per kilogram.

(2) Pallet nails, made of galvanized iron, with a specification of 90mm3/2, the retail price is 7 yuan per kilogram.

It is used for floor grille mixed with Meigu nail (floor grille expansion nail), it can be used per kilogram, and the use is 3-4m. Meigu nail floor grille expansion nails, special for percussion interior decoration.

Specifications: 10X98 50 capsules per pack, retail price 22.70 yuan. The retail price of 50 tablets per pack of 10X78 is 19.50. The retail price of 50 tablets per pack of 8X78 is 14.30. Among them: 10-refers to the expansion thickness, 98-refers to the length of the screw.

The sales of floor grille expansion nails and floor nails are both very good. Last year, the sales of Meigu nails reached 60,000 yuan, an average of about 5,000 yuan per month. Floor nails sold 136,000 last year, ranking first among various decorative nails.

Three, floor spring door closer

A certain percentage of the floor springs in the small hardware can make the door close automatically. Low spring brands are imported and domestically produced. Imported products such as GEZE 480 and 490 floor springs made in Germany. Doma 84 type 75 type floor spring. New star HS222 made in Japan, etc.

Because the price of imported floor springs is relatively high, ranging from 700 yuan to 3,000 yuan, the sales volume is not large. Customers with special needs will still choose it. The CMT crown floor spring sold by Dongfeng Company is the best in the market. Because the sales situation in the market is good and the prices are moderate, it is inevitable that there will be fake and shoddy goods, most of which come from various sources. From appearance = specifications, shape, and even packaging are the same. However, due to poor quality, rough workmanship, and a relatively short service life.

The characteristics and design principles of mold strong spring

This article introduces the characteristics and design principles of the die strong spring, and theoretically analyzes the stress, stiffness and deformation of the special-shaped wire die spring and the round wire spring. The design method of the die strong spring is briefly described, and the main problems affecting the development of the die strong spring are pointed out. In recent years, with the development of the mold industry, the number and variety of mold springs, especially special-shaped cross-section steel wire mold springs, are increasing. The special-shaped cross-section die spring has the characteristics of high rigidity, long life, and small size. But the development of its design theory is relatively slow. At present, in addition to the more mature design methods of square section strong springs, the design methods of other section strong springs are basically based on the specific section through the test, find the correction coefficient to obtain the empirical design formula of the specific section, now the characteristics of this type of spring Give an introduction to the design problem. This problem is a problem that people who use this kind of spring care about and must figure out. The following is a comparison between a square section and a round section coil spring. In the same space, the load-bearing capacity of a square section steel wire spring is 43-48% higher than that of a round section spring. Obviously, the rectangular spring should be more than 50%. From the analysis that excessive use stress is the main reason for spring damage, under the same conditions, the service life of the special-shaped section wire spring is 13-14% longer than that of the round section wire spring. The special-shaped cross-section wire spring can produce a large amount of deformation. Special-shaped wire springs are heavy. The linearity is better than that of the circular section spring, that is, the stiffness tends to be more constant. Especially springs with long sides wound parallel to the axis. The scope of application is limited: It can be seen from the analysis that if the special-shaped cross-section material spring cannot fully utilize its advantages, it will not produce economic benefits. Under what circumstances should it be used?
(1) The design load cannot be achieved with circular cross-section materials.

(2) Replace the circular cross-section compound spring.

(3) When the required deformation cannot be achieved with the round material spring. Where the spring installation space is small. Where strict spring characteristics are required.

2. Design principles of mold spring

1. The selection of allowable stress [τ] of the spring material should be mainly considered to ensure the fatigue life of the spring. The dynamic life of springs is generally divided into three categories:

Class I: The number of alternating loads is 106;

Class Ⅱ: The number of alternating loads is 10&3;—105;

Class III: The number of times of bearing the alternating load is less than 10&3;;

2. The material width-to-thickness ratio (a/b) should not be too large, and the winding of the spring should not be too small.

3. When designing non-rectangular shaped cross-section springs, it is necessary to derive and draw curves or calculation formulas in different rotation ratios, different width to thickness ratios, deformation correction coefficients (τ) and shear stress correction coefficients (β).

4. According to the given conditions and constraints, choose a design method that is simple to calculate and select reasonable parameters.

Three remaining problems

1. The low standardization of mold design limits the development speed of standardized mold springs.

2. The degree of standardization of mold springs is low. At present, except for the QC7111-7113 standard formulated by our institute for the automotive industry, there is no official national standard or industry standard in China. The lack of standard selection by mold designers is an urgent problem to be solved.

3. The design theory is not perfect. At present, the rectangular cross-section spiral spring is more mature, but the selection of its tolerance is still inconclusive. The spiral springs with special-shaped cross-sections are all based on rectangular cross-sections, which have been modified by experiments.

4. There are no designated factories producing special-shaped cross-section materials, especially oil-quenched and tempered steel wire suppliers that do not have such materials. However, the materials reformed by the spring manufacturer itself have unstable quality and high cost, which affects the popularization and application of this type of spring.

5. There is no special coil spring equipment for producing such springs. The spiral spring winding ratio of the mold is generally less than

4. The domestic spring coiling machine is suitable for springs with a winding ratio above 4.

The development of spring processing technology

At present, the processing equipment and production lines of mechanical springs are developing towards the depth and breadth of numerical control (NC) and computer control (CNC). However, with changes in spring materials and geometric new shapes, processing techniques have also developed.
1) The suspension spring with variable spring outer diameter, variable pitch and variable steel wire diameter (three-variable) realizes moldless plastic processing. Since the development of three-variable springs, tapered steel bars have been used for winding processing on CNC lathes, but the yield and price are not ideal. Now it is changed to use the spring coiling machine under the heating state to control the roll speed and drawing force to obtain the required cone shape, and use the processing waste heat for quenching.

2) The hollow stabilized spring rod is rolled and welded with low carbon boron steel plate.

3) The torsion bar is made of high-purity 45 steel. After high-frequency quenching, the surface has high hardness and large residual compressive stress, thereby improving fatigue life and anti-relaxation ability.

4) The leaf springs widely used in electronic products are basically formed by stamping and automatic bending. At present, it is mainly to develop the joining technology of composite materials.

(1) Cold forming process of spring

1) One-time automation of cold forming process. The cold forming machine has now developed to 12 jaws. The steel wire in the range of (0.3-14)mm can basically be formed at one time by the 8-jaw forming machine. The current development direction of forming process equipment: ①Increase the forming speed, the main development trend is to increase the forming speed of the equipment, that is, the production efficiency; ②Improve the durability of the equipment by improving the precision of the equipment parts and strengthening the heat treatment effect; ③Increase the length sensor and Laser rangefinder, automatic closed loop control manufacturing process for CNC forming machine.

2) Cold forming process range capability. At present, the maximum specification of large wire diameter spring coiling machine can reach 20mm, =2000MPa, and the winding ratio is 5. The cold forming process of variable diameter or equal diameter material Minic-Block spring and eccentric spring still has limitations.

(2) Hot forming process of spring

1) Hot forming process speed capability. At present, our country only has CNC 2-axis hot coiling machine for forming on (9~25)mm specifications, with a maximum speed of 17 pieces per minute. Compared with developed countries, the gap is large.

2) Large spring hot forming process control ability. Because there is only a CNC2-axis hot coil spring machine, the shape control is less effective in three directions, and the accuracy is poor; and there is no automatic bar rotation control and adjustment mechanism, so the hot coil spring forming process is level

Characteristics of coil springs

Due to the structural characteristics of the cylindrical spiral spring, within the elastic deformation range of the material, the relationship between the spring load “P” and the deformation amount “F” is not completely linear. As the deformation increases, the helix angle also increases. , The deviation of load and deformation from linearity is also large. However, the relationship between load and deformation is basically linear within the working deformation range of a spring, and the deviation from linearity is generally 1% to 3%.

Introduction to the basic knowledge of copper

1. Natural attributes
Copper is one of the earliest ancient metals discovered by mankind. Mankind began to use copper more than 3,000 years ago.

Metal copper, element symbol Cu, atomic weight 63.54, specific gravity 8.92, melting point 1083oC. The pure copper is light rose or light red, and after a copper oxide film is formed on the surface, the appearance is copper-colored. Copper has many valuable physical and chemical properties, such as high thermal and electrical conductivity, strong chemical stability, high tensile strength, easy welding, corrosion resistance, plasticity, and ductility. Pure copper can be drawn into very thin copper wires and made into very thin copper foil. It can form alloys with zinc, tin, lead, manganese, cobalt, nickel, aluminum, iron and other metals.

The development of copper smelting technology has gone through a long process, but so far copper smelting is still dominated by fire smelting, and its output accounts for about 85% of the world’s total copper output. 1) Pyrometallurgy is generally to first increase the raw ore containing a few percent or a few thousandths of copper to 20-30% through beneficiation, and use it as a copper concentrate in a closed blast furnace, reverberatory furnace, electric furnace or flash furnace For matte smelting, the produced matte (copper matte) is then sent to a converter for blowing into blister copper, and then oxidized and refined in another reverberatory furnace to remove impurities, or cast into an anode plate for electrolysis to obtain a high grade 99.9% electrolytic copper. The process is short and adaptable, and the recovery rate of copper can reach 95%. However, because the sulfur in the ore is discharged as sulfur dioxide waste gas in the two stages of matte production and conversion, it is difficult to recover and easy to cause pollution. In recent years, molten pool smelting such as the silver method and the Noranda method, as well as the Mitsubishi method in Japan, has gradually developed towards continuous and automated pyrometallurgy. 2) Modern wet smelting includes sulfuration roasting-leaching-electrodeposition, leaching-extraction-electrodeposition, bacterial leaching, etc., suitable for heap leaching and tank leaching of low-grade complex ore, copper oxide ore, copper-bearing waste ore Or leaching in place. The hydrometallurgical technology is gradually being promoted, and it is expected that it will reach 20% of the total output by the end of this century. The introduction of hydrometallurgy has greatly reduced the cost of copper smelting.

2. Classification of copper and copper products

1. Classification according to the existing forms in nature

Natural copper-the copper content is above 99%, but the reserves are very small;

Copper oxide ore—–not many

Copper sulfide ore-the copper content is extremely low, generally around 2-3%. More than 80% of the world’s copper is refined from copper sulfide ore.

2. Classified by production process

Copper concentrate-ore with higher copper content selected before smelting.

Blister copper-the smelted product of copper concentrate, with a copper content of 95-98%.

Pure copper-copper with a content of more than 99% after smelting or electrolysis. Fire refining can obtain 99-99.9% pure copper, and electrolysis can make the purity of copper reach 99.95-99.99%.

3. Classified by main alloy composition

Brass—–copper-zinc alloy

Bronze—–copper-tin alloy, etc. (except for zinc-nickel, alloys with other elements are called bronze)

Cupronickel—–copper-cobalt-nickel alloy

4. Classified by product form: copper tube, copper rod, copper wire, copper plate, copper strip, copper strip, copper foil, etc.

3. Copper product number and quality standard

The quality standard for the subject matter of the copper futures contract before September 1997 was the GB466-82 standard, and the delivery product was No. 1 copper. From September 1997 to August 1998, GB466-82 and GB/T-467-1997 were both The standards are implemented at the same time. Since September 1998, all GB/T467-1997 standards have been implemented. Both high-purity copper cathodes and standard copper cathodes can be delivered. There is no quality premium or discount, only brand premiums and discounts.

1. The chemical composition of high-purity cathode copper (Cu-CATH-1): Cu+Ag is not less than 99.95, and the total impurity content does not exceed 0.0065 (the impurity classification content is omitted).

Copper is a widely used metal with unique advantages in terms of conductivity, conductivity, tensile strength, extensibility, corrosion resistance, and fatigue resistance. It is mainly used in industrial equipment manufacturing, electrical Industry, communication industry, construction industry, transportation industry, fastener industry, etc. The numerous uses also make the price of copper very sensitive to changes in supply and demand and fluctuates widely. The close correlation between copper and social life makes copper demand directly related to changes in economic conditions.

In addition to mining, the supply of copper can also be obtained through secondary recovery. The main copper producing countries in the world are Chile, the United States, Canada, Zambia, Zaire and Peru. my country is also a major copper producer, and its output in 1991 ranked seventh in the world. my country’s copper production is mainly concentrated in Jiangxi, Xiangbei, Gansu, Tianjin, Shanghai, Anhui, Liaoning, Shanxi, Hunan, and Yunnan. However, due to the low grade of my country’s copper ore, unsatisfactory resource conditions, and a large demand for copper, copper and copper alloys are imported every year to meet the shortage of supply.

In 2001, the global consumption of copper was about 14.885 million tons, and copper consumption was concentrated in developed industrial countries. The United States is the largest copper consumer. In 2000, it consumed 2.923 million tons, accounting for about one-fifth of the world’s total consumption, followed by China 1.75 million tons, Japan 1.327 million tons, and Europe 4.385 million tons. From an industry perspective, the electrical industry and the construction industry consume the most copper.

In 2002, the world’s refined copper production was 15.02 million tons, consumption was 14.90 million tons, and the supply and demand gap was 120,000 tons. The balance of supply and demand in 2001 was an oversupply of 948,000 tons, and the contradiction between supply and demand has been greatly improved.

The scope of use and development space of gas springs

As a new term, gas springs have gradually appeared in some Internet newspapers, and its practical range has also developed from some basic car trunk and hood support to the machinery manufacturing industry, which is used for equipment accessory support and equipment shock absorption. As the support of toolbox cover, medical industry, fitness equipment and other fields, as its practicality is further recognized, the scope of use is also becoming wider and wider. Some people in the industry ask: The application range of gas springs is becoming wider and wider. Does it have an impact on the original telescopic spring? I personally think that it will not cause an impact on the original spring. Of course it will have a certain impact, because most of the gas springs are used. It is an innovation in the product design of some companies. For example, the rear box of Sanlun motorcycles was originally supported by iron rods (they are still used). Now the gas springs are very light, convenient and labor-saving. Some units don’t know. His design has certain limitations, but companies must be innovative in order to stay ahead of their peers. I have been making gas springs for many years. Experience tells me that many manufacturers are now trying out our gas springs, and they have all used them formally. The effect is obvious, but some companies don’t know what a gas spring is, let alone its function, so they will In a passive position, I hope that some industries, such as: machinery manufacturing, automobile and motorcycle, transportation equipment, toolbox and other box manufacturing, medical treatment, fitness, kitchen cabinets, etc., if you need to understand the function and use of gas springs, please consult me , I will definitely advise you.

my country’s spring industry presents three major development trends

Some experts in the spring industry in my country believe that with the development of the main engine, the spring product market in my country will also grow simultaneously. It is estimated that the sales of the whole industry will exceed 4 billion yuan by 2010, and the proportion of the automobile and motorcycle industries in the spring market will be More than 50%. At the same time, in order to adapt to market changes, the spring industry will show new development trends in the next few years:
-A new combination appears. In the next few years, my country’s spring industry will still be dominated by small companies, but some advantageous companies start from the market and business strategy, use the capital, technology and talent advantages in their hands to merge and acquire some companies to obtain the necessary production factors and market resources , Most of the state-owned and collective enterprises in the spring industry will be transformed into joint-stock or private enterprises.

——Price competition turns to technology and quality competition. With the increasingly fierce market competition, the profit margin of the spring industry has become smaller and smaller. In addition, the main engine manufacturers have higher and higher requirements for the quality of accessories. Enterprises can no longer rely on simple price reductions to win the market. Technology and quality have become the key to competition. From July 1, 2006, my country’s auto parts tariffs will be reduced to 10%, and the final prices of suspension springs, valve springs, stabilizers and other products for the automotive industry will gradually be in line with international prices, and for mini-cars , The products of the van have undergone fierce market competition. The current price has a certain degree of competitiveness compared with the international market, but the quality level cannot compete with similar products. The prices of other products, especially those for motorcycles and some small springs, are already lower than the international market prices. Therefore, similar foreign products pose no threat to us in terms of price, and competition is mainly manifested in quality.

——Products are developing towards lightweight and high reliability. Roughly estimated, in 2010, the annual demand for suspension springs in China’s automobile industry was about 8 million pieces, and the annual demand for valve springs was about 30 million pieces (excluding motorcycles and diesel engines). The technical development trend of these two springs is generally lightweight (high stress) and high reliability. For the currently available special-shaped cross-section suspension springs and valve springs, due to high material prices and complex manufacturing processes, the production cost is higher than that of round-section springs. Therefore, there is no sign that the special-shaped section springs will completely replace the round-section springs.

The working principle of spring-loaded safety valve

The working principle of spring-loaded safety valve
The working principle of the spring-loaded safety valve is: when the gas pressure under the safety valve disc exceeds the pressing force of the spring, the disc is pushed open. After the valve flap is opened, the exhaust gas will act on the valve flap clamping ring due to the rebound of the lower adjusting ring, so that the valve will open quickly. As the valve flap moves up, the gas impacts on the upper adjusting ring, causing the exhaust direction to tend to be vertical downward. The reaction force generated by the exhaust pushes the valve flap upwards and keeps the valve flap in a certain pressure range. Sufficient lifting height. With the opening of the safety valve, the gas is continuously discharged, and the gas pressure in the system gradually decreases. At this time, the force of the spring will overcome the gas pressure acting on the valve flap and the reaction force of the exhaust, thereby closing the safety valve. Valve spring

Heat treatment of high speed steel

High-speed steel is the main material for manufacturing various cutting tools (or molds) and is currently widely used. When a machined tool is working, due to friction, the temperature of the part where the tool is used will inevitably increase. For example, when the cutting speed of the tool is 10-20M/min, the temperature of the blade is 200-320℃. When the turning speed is 50-80M/min, the blade temperature is 500-600°C. As the processing object changes, in some special cases, the blade will reach 670℃, and even the temperature of some warm extrusion mold parts will reach 700℃. This requires our cutting tools (or tools and moulds) to use corresponding reasonable tool materials, which should have high hardness, high strength, high wear resistance, high red hardness and certain toughness necessary for tool materials. In order to meet the above requirements, the heat treatment of high-speed steel must be strictly controlled from annealing to quenching. According to the service conditions of various tools, the heat treatment process parameters must be reasonably selected to achieve the most ideal performance and minimum deformation. For some tools with special requirements, the surface hardness and wear resistance must be improved by chemical heat treatment.

Coil springs for suspension technical conditions

This standard is re-established on the basis of JB/T 3823-1984 “Technical Conditions for Spiral Springs for Automobiles” and JB/T 3824-1984 “Test Methods for Spiral Springs for Automobiles”. The above two standards were abolished in 1999. Compared with JB/T 3823-1984 “Technical Conditions for Spiral Springs for Automobiles” and JB/T 3824-1984 “Test Methods for Spiral Springs for Automobiles”, the main changes are as follows:
—–Reference Standard:

—————Specific regulations on hardness and decarburization:

—————Specific regulations for surface anticorrosion test:

—————Specific regulations are made on the product sampling method:

—————Description of verticality:

—————Specific regulations are made on the pitch uniformity:

—————Tolerance of the outer diameter of the end ring.

This standard was proposed by China Machinery Industry Federation

This standard is under the jurisdiction of the National Spring Standardization Technical Committee (SAC/TC235)

Drafting organizations of this standard: China Spring Factory, Guangzhou Huade Automobile Spring Co., Ltd., Shandong Lianmei Automobile Spring Co., Ltd., Zhuji Jinbao Automobile Spring Factory

The main drafters of this standard: Jiang Ying, Long Aihua, Yang Weiming, Liu Cuiling, Jin Guoxiang.