Stainless steel screw structure and classification Stainless steel screw purchase and installation skills
Stainless steel screws usually refer to steels that are resistant to the corrosive effects of air, water, acids, alkali salts, or other media. According to the different composition of the alloy, the stainless steel and acid resistance are respectively emphasized. Although some steels have a non-rusting nature, they are not necessarily resistant to acids, and acid-resistant steels are generally non-rust-resistant. Austenitic stainless steels are used to produce fasteners. In people's daily lives, the stainless steel often referred to is austenitic stainless steel. We use stainless steel fasteners, the main raw materials used are austenite 302,304,316 and "low nickel" 201, stainless steel screws are generally not easy to rust, very durable.
Stainless steel screw structure
Retaining ring:
It is installed in the axis groove or hole groove of the machine and equipment and acts to block the left and right movement of the part on the shaft or in the hole.
pin:
Mainly for the positioning of parts, and some can also be used to connect parts, fix parts, transmit power or lock other fasteners.
rivet:
A type of fastener consisting of two parts, the head and the shank, is used to fasten two parts with through-holes into a single piece.
Assembly:
Refers to a combination of supply of fasteners, such as the combination of machine screws (or self-tapping screws) and flat washers (or spring washers, lock washers).
Stainless steel screw pictures
Wyeth Thread:
It is a common thread for British inch size fasteners. Its thread angle is 55°. The specifications of Wyeth's thread are used to indicate the nominal diameter (in units) and the number of teeth per inch, and the unit of measurement is the symbol 〞. For example: 1/4〞-20 represents a coarse tooth with a nominal diameter of 1/4 inch. Represents one inch of teeth.
Unified standard thread:
It is a common screw thread for American inch fasteners. Its thread angle is 60°. Its specification is represented by numbers (inches of nominal diameter <1/4 inch or nominal diameter (≥1/4 inch), number of teeth per inch, and code (UNC-coarse, UNF-fine).
For example: 1/2〞-13UNC, which means that the nominal diameter is 1/2 inch, and 13 standard teeth are used for uniform standard threads per inch.
Stainless steel screw material classification
Stainless steel screws are classified into austenitic stainless steels, ferritic stainless steels, martensitic stainless steels, and precipitation hardened stainless steels. The choice of stainless steel screws is also principle, starting from what, let you choose the stainless steel screws you need. After comprehensive and comprehensive consideration of these five aspects, the final selection of the grade, type, specification and material standard of the stainless steel screws
Austenitic stainless steel: The most basic alloying elements for austenitic stainless steels are chromium and nickel. Representative grades are chromium-nickel austenitic stainless steels containing about 18% chromium and about 8% nickel, often referred to as 18 -8 stainless steel. The elemental ratio of chromium and nickel basically ensures that the steel structure is stable austenite
Ferritic stainless steel: Type 430 ordinary chromium steel, its corrosion resistance and heat resistance is better than 410 type, magnetic, but it can not be heat-treated, suitable for corrosion resistance and slightly higher heat resistance, strength General stainless steel stainless steel screws are required.
Martensitic stainless steel: Type 410 and Type 416 can be heat-treated, hardness 35 ~ 45HRC, good machining performance, for general-purpose heat-resistant corrosion-resistant stainless steel screws.
Type 416 contains a slightly higher sulphur content and is free-cutting stainless steel. Type 420, sulfur content ?R0.15%, mechanical properties increase, can be heat treatment, maximum hardness value of 53 ~ 58HRC, for stainless steel screws that require higher strength.
stainless steel screw
Precipitation-hardening stainless steel: 17-4PH, PH15-7Mo, they can get higher strength than the usual 18-8 stainless steel, and therefore are used in high-strength, corrosion-resistant stainless steel stainless steel screws.
A-286, a non-standard stainless steel, has higher corrosion resistance than commonly used Type 18-8 stainless steel, and still has good mechanical properties at elevated temperatures. Used as a high-strength, heat-resistant, corrosion-resistant stainless steel screw that can be used up to 650 to 700°C.
Austenite stainless steel: The four models commonly used are 302, 303, 304, and 305, which are the so-called "18-8" austenitic stainless steels. Whether it is corrosion resistance or its mechanical properties are similar. The starting point for the selection is the production process of stainless steel screws, which in turn depends on the size and shape of the stainless steel screws and on the number of production.
Model 302 is used for machining screws and self-tapping bolts.
Type 303 To improve the cutting performance, a small amount of sulfur is added to the Type 303 stainless steel and used to process nuts using bar stock.
Type 304 is suitable for machining stainless steel screws using hot boring technology, such as longer size bolts, large diameter bolts, which may exceed the scope of the cold heading process.
Type 305 is suitable for machining stainless steel screws with cold heading, such as cold formed nuts and hexagon bolts.
Types 309 and 310, their Cr content and Ni content are higher than 18-8 stainless steel, suitable for stainless steel screws working at high temperatures.
Types 316 and 317, both of which contain the alloying element Mo, therefore have higher temperature strength and corrosion resistance than Type 18-8 stainless steel.
Types 321 and 347, Type 321 contain relatively stable alloying elements Ti, 347-type containing Nb, thereby improving the material's resistance to intergranular corrosion. Suitable for stainless steel standard parts that do not anneal after welding or service at 420～1013°C.
Stainless steel screw pictures
Stainless steel screw purchase skills
Stainless steel screws are screws made of steel that resist the corrosive effects of air, water, acids, alkali salts, or other media. If you want to buy the stainless steel screws you need, consider the factors.
1. The corrosion resistance and heat resistance of the selected stainless steel screw are good;
2, whether the performance is high, whether it can be strengthened by heat treatment;
3, the production process aspects of the material processing performance requirements;
4, stainless steel screw specifications, material standards how.
Stainless steel screws are mainly used for: environmental protection equipment, medical equipment, communications equipment, electrical facilities, electronic products, instrumentation, food machinery, petrochemicals, shipbuilding equipment, pump and valve pipelines, building curtain walls, open air applications, sports facilities, outdoor decoration and so on.
Stainless steel screw installation method
1. Select an alloy drill that matches the inner diameter of the inner expansion bolt and drill it with reference to the length of the inner expansion bolt. Drill the hole deep enough for your installation and clean the hole.
2. Install flat washers, spring washers, and nuts. Turn the nuts to the bolts and ends to protect the threads. Insert the inner expansion bolts into the holes.
3. Turn the wrench until the washer is flush with the surface of the fixture. If there is no special requirement, tighten it by hand and then use a spanner to turn three to five turns.
Stainless steel screw installation notes
1, drilling depth: the depth of the construction of a good or deeper than the length of the expansion tube about 5 mm. As long as it is greater than or equal to the length of the expansion tube, the length of the inner expansion bolt left in the ground is equal to or less than the length of the expansion tube.
2. The requirement for the inner expansion bolts on the ground is of course the harder the better. It also depends on the condition of the object you need to fix. The strength of the concrete installed in the concrete (C13-15) is five times that of the brick.
3. After an M6/8/10/12 internal expansion bolt is properly installed in the concrete, its ideal large static force is 120/170/320/510 kg.