Carriage bolts are divided into large semi-circular head carriage bolts (corresponding to standard GB/T14 and DIN603) and small semi-circular head carriage bolts (corresponding to standard GB/T12-85) according to head size.

Carriage bolts can also be called square neck bolts. They consist of a square neck under a round head, so they are also called square neck bolts. The carriage bolt is composed of head and threaded screw. It needs using in conjunction with nut to fasten and connect two parts with through holes. Another feature of the carriage bolt is that its threaded rod is a cylinder with an external thread.

A carriage bolt consists of mushroom head and screw (with external threads), it needs matching with nut to fasten and connect two parts with through holes. One of the widely used carriage bolts is standard DIN603 with metric M5 to M20 thread.

The strength grade of flange bolts is selected according to the working pressure. If the working pressure is less than 1Mpa, you can choose grade 4.8, and if it isbetween 1~4.5Mpa, you can choose grade 8.8 high-strength bolts.

Flange bolts are integral bolts consisting of a hexagon head, flange (round washer under the hexagon) and screw (with external thread). It needs to be matched with nut, which is used to fasten part connecting two through holes.

Head of the flange bolt is hexagonal.The bolt consists of hexagon, round disc and threaded rod. The disc surface is serrated, which is anti-skid and anti-loosening. The flange bolt needs to be matched.with nut for fastening work.

Track bolts are also known as high-strength fishtail bolts. Generally, they are mainly used in the connection of track joint splints to play a fixed role. Sometimes track bolts can also replace hexagonal bolts.

Oval neck bolts are also called fishtail bolts, which are widely used in the industry. They are very convenient to use and the price is relatively low. Fishtail bolts are mainly used in the track laying of metallurgical industry, coking industry and iron and steel industry, and the connection between the rail and the rail joint is fastened.

High-strength fishtail bolts are usually used on railway tracks. In the comprehensive use environment, most of them choose surface treatments such as black oxide and hot-dip galvanizing to improve the anti-corrosion ability in outdoor environments, which can make the service life of fishtail bolts longer and more stable

Oval neck bolts, also known as fishtail bolts, egg neck bolts, and track bolts.It has a round head, oval neck and then the thread with different length. That is why it is called round head oval neck bolt or egg bolts too.

DIN933 is a German standard hexagon bolt, which is suitable for full thread hexagon bolts with a diameter of M1.6-M52. The general carbon steel grades are mainly 4.8, 8.8 and 10.9. The common standards are DIN931 and DIN933 for metric coarse thread; DIN960 and DIN961 are for metric fine thread hex bolts.

There are different grade for hex bolts, such as 4.6, 4.8, 5.6, 6.8, 8.8, 9.8, 10.9, 12.9, etc. Among them, the hexagonal bolts of grade 8.8 and above are made of low-carbon alloy steel or medium-carbon steel. It reaches different grade after heat treatment (quenching, tempering).