The vast majority of material for steel fasteners, as a work in the fastener industry personnel, it is necessary to understand the changes in and application of the distinction, in the case of technical staff, it would have a better understanding.

　　I understand that the author on the application of the material, in the light of relevant information, and we share this knowledge, for just in this industry can be used as a guide for soil, senior people, we can further explore the

　　Now we are the standard pieces of materials commonly used are:

　　ISO (international)

　　GB (China)

　　DIN (Germany)

　　AISI / SAE (U.S.)

　　JIS (Japan)

　　External bolt material thread

　　Mechanical properties are not required or ISO Class 4.8 SAE Grade 1-2, such as low-carbon steel fasteners, and Q235A SAE 1015 DIN C15 sufficient to simply do not want heat treatment, cold working directly made, and the slightly higher level of fastening items such as: ISO Class 6.8 SAE Grade 3-4 carbon content it will need more than 0.2% in the steel, such as C1020 C1022 Ml20 ML35 and so on, what type of screw does not require heat treatment and cold working to meet the requirements of full strength. In fact the higher carbon content, the more difficult for Cold Forming and 6.8 there is no need to screw Big timber Small with special circumstances is another matter.

　　We are the most commonly used is the ISO Class 8.8 SAE Grade 5 of the screw, the general use of carbon steel, ML35 SAE 1035 DIN 35 JIS SWRCH35K after heat treatment (quenching + tempering), can also be used, such as SAE5140 40Cr alloy elements to increase heat treatment Hardenability very helpful, so big screw specifications have the option of using alloy steel, carbon steel will not lead us to use in the center of the site used to say "impenetrable quenching" the existence of the phenomenon.

　　ISO Class 9.8 10.9 SAE Grade 8 will need to low-to medium-alloy steel material, after heat treatment (quenching + tempering), alloy materials used in the mechanical properties of materials have a very good combination of materials commonly used for the 40Cr 35CrMo SAE5140 SCM435 SAE4135 SAE4137 JIS SCr440 (H) DIN 41Cr4 such as, in fact, # 45 can also meet the requirement of the mechanical properties, but the mechanical properties of the integrated area slightly less than steel.

　　ISO Class12.9 SATM A574 is a very high mechanical performance requirements of high strength bolts are used in heat-treated carbon alloy steel (quenching + tempering), such as SCM435 35CrMo SAE 4137 SAE4135 DIN 34CrMo4, if such a high strength bolts pickling surface treatment to go through this process, we will have a hydrogen embrittlement phenomenon, we must have the processes dehydrogenase (in particular the existence of cusp of the fastener), or else I will die the miserable.

　　Threaded nut and other materials used in

　　There is no mechanical or performance requirements of the ISO Class 5-6 SAE Grade 3-4 or C1010 Q235A generally C15, do not require heat treatment, cold working can be. ISO Class 8, SAE Grade 5, the general use Ml35 SAE1035 DIN C35, small size nut do not need to heat up to the requirements of the Agency to the mechanical properties, specifications big to go through treatment (quenching + tempering), which GB3098.2 that very clear.

　　ISO Class 10, SAE Grade 8 steel usually used in heat-treated to achieve its strength. Such as medium carbon steel SAE1035. It is important to note, different nuts and bolts, the main force to compression rather than mainly done, therefore the strength of more than nuts and materials, but also and a lot of factors, including accuracy, pitch, nut chamfer , nut thickness ......

　　Materials used for flat washers

　　No mechanical performance requirements of the general use of angle flat gasket material manufacturers, such as the Q235A, have high hardness, but not when the thick sheet can be rolled about the hardness required. Mats, such as nut shells used in generally washers 65Mn 70 # or S 50CM-S 70CM manufacturers must go through a heat treatment (quenching + tempering)

　　Rivet, pin-type

　　Rivet, pin-type material to be used with the bolts in general, but not too high hardness of some rivets, and even some requests HRB60 the following, the general normalization of the material hardness of HRB70-80, so some have to go through to achieve the performance requirements of annealing.

　　Self-Tapping Screws C1018 C1020 C1022 general use, such as materials, but some domestic manufacturers to reduce costs and cut corners using 18 # 15 # 20 # more with some manufacturers use Q235A, and then deal with the surface carburization done, so that made its self-tapping screw the center of toughness fail and easy to break.

　　I do not know much about stainless steel fasteners, as if SUS304 is very commonly used.

　　Other special requirements of materials

　　If companies do fasteners used for welding, arc welding and gas welding of materials in general are not required. If the client is used for spot welding, it should come with low-carbon steel, if we must increase the intensity, you can use some elements of low-carbon Mn containing materials higher. Here is just a very simple example, many of them are in the actual production can be noted.

　　When customers use a certain designated grades of material, and the company at the absence of such material, or such material is not easy in the market, purchasing, customers can learn about the use of the fasteners, in conformity with the requirements of the mechanical properties can be submit a written application for substitution of materials. Procurement customers a number of fasteners is not very professional, the choice of materials are not necessarily the best, as we are manufacturers specializing in the production of fasteners, you can give customers a better proposal to double the interest received.

　　Course materials fasteners should be noted that more than these, such as the materials used must be out of date before the period (before I write a special article in this regard), the surface rust bad some of the materials used in the manufacture of threaded fasteners or the whole the need for grinding the surface of the fasteners, materials are organized by the Center should not be used in the manufacture of cavity polishing head screws ......

　　Application of the ever-changing materials and proper use of funds, for the chicken soup of water, are used improperly, the result is the waste of a small, additional cost, the loss of the company may have to group a lot of money!