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China Suppliers Factory Hot Dipped Galvanized Hdg Din933 Hex Head Bolts for Ultimate Durability
Production Parameter
| Thread size d |
M12 | M16 | M20 | M22 | M24 | M30 | |||
| P | pitch | 1.75 | 2 | 2.5 | 2.5 | 3 | 3.5 | ||
| ds | Max | 12.7 | 16.7 | 20.84 | 22.84 | 24.84 | 30.84 | ||
| Min | 11.3 | 15.3 | 19.16 | 21.16 | 23.16 | 29.16 | |||
| s | Max | 18 | 24 | 30 | 34 | 36 | 46 | ||
| Min | 17.57 | 23.16 | 29.16 | 33 | 35 | 45 | |||
| e | Max | 20.7 | 27.7 | 34.6 | 39.3 | 41.6 | 53.1 | ||
| Min | 19.85 | 26.17 | 32.95 | 37.29 | 39.55 | 50.85 | |||
| dw | Min | 16.5 | 22 | 27.7 | 31.35 | 33.2 | 42.7 | ||
| c | Max | 0.6 | 0.8 | 0.8 | 0.8 | 0.8 | 0.8 | ||
| Min | 0.15 | 0.2 | 0.2 | 0.2 | 0.2 | 0.2 | |||
| da | Max | 14.7 | 18.7 | 24.4 | 26.4 | 28.4 | 35.4 | ||
| r | Min | 0.6 | 0.6 | 0.8 | 0.8 | 0.8 | 1 | ||
| k | Max | 7.95 | 10.75 | 13.4 | 14.9 | 15.9 | 19.75 | ||
| Min | 7.05 | 9.25 | 11.6 | 13.1 | 14.1 | 17.65 | |||
| b | Single nut bolt | according to | d + 9 | d + 9 | d + 8 | d + 9 | d + 7 | d + 6 | |
| nominal | 21 | 25 | 28 | 31 | 31 | 36 | |||
| Double nut bolt | according to | 1.8d + 9 | 1.8d + 10 | 1.8d + 10 | 1.8d + 13 | 1.8d + 11 | 1.8d + 8 | ||
| nominal | 30.6 | 38.8 | 46 | 52.6 | 54.2 | 62 | |||
Production Description
HDG generally refers to hot-dip galvanizing. Hot-dip galvanizing is to make the molten metal react with the iron matrix to produce an alloy layer, so that the matrix and the coating are combined. Hot-dip galvanizing is to pickle the iron and steel parts first, in order to remove the iron oxide on the surface of the iron and steel parts, after pickling, it is cleaned in a tank of ammonium chloride or zinc chloride aqueous solution or a mixed aqueous solution of ammonium chloride and zinc chloride, and then sent to the hot dip coating tank. Hot-dip galvanizing has the advantages of uniform coating, strong adhesion and long service life.
The countersunk head of hot dip galvanized bolts is usually used where the connection is required. It is a non-standard part in the shape of a U and is therefore also known as a U-bolt. Hot-dip galvanized bolts with threads at both ends can be used in combination with nuts. The utility model is mainly used for fixing tubular or flaky objects.
The corrosion resistance is mainly determined by the thickness of the galvanized layer, so the thickness measurement is often the main basis for judging the quality of the galvanized layer. The angle and speed of the solution also have a great influence. Therefore, it is practically impossible to obtain a completely uniform coating thickness.
Frequently Asked Questions
1. What is an HDG DIN933 hex head bolt?
An HDG DIN933 hex head bolt is a fully threaded hexagonal head bolt manufactured in accordance with the DIN 933 standard, treated with a hot-dip galvanized (HDG) coating to provide superior corrosion resistance.
2. What are the main benefits of hot-dip galvanizing (HDG) for bolts?
Hot-dip galvanizing offers key advantages such as a highly uniform protective coating, strong adhesion to the steel base through a zinc-iron alloy layer, and a significantly extended service life even in harsh outdoor environments.
3. How is the quality of the hot-dip galvanized layer evaluated?
The quality of the galvanized layer is primarily evaluated by measuring its thickness, as thickness directly determines corrosion resistance. Other factors like solution angle and speed during processing also affect the quality.
4. Can HDG bolts be used with standard nuts?
Due to the thickness of the hot-dip galvanized coating, HDG bolts are typically paired with hot-dip galvanized nuts that are tapped slightly oversized (overtapped) to ensure a proper fit without damaging the protective zinc layer.
5. Why is the thickness of the galvanized coating not completely uniform?
During the hot-dip process, the angle of withdrawal, the speed of the solution run-off, and the thread geometry naturally cause minor variations in zinc accumulation, making a completely uniform thickness practically impossible.