Spesifikasi standar dan aplikasi sekrup heksagonal dan sekrup heksagonal eksternal DIN933.

What is DIN 933? The Backbone of Industrial Fastening

In the world of mechanical engineering, the DIN 933 standard refers to hexagon head screws with a thread that extends all the way to the head (fully threaded). Often referred to interchangeably as hex bolts, these fasteners are the universal solution for high-torque assembly. At Kekuatan Abadi, we specialize in high-grade stainless steel versions of these screws, ensuring durability in the most demanding environments.

DIN 933 vs. GB/T 5783: Understanding the Subtle Differences

A common question we receive from global procurement teams is whether DIN 933 and the Chinese standard GB/T 5783 are interchangeable. While they are functionally compatible in most scenarios, engineering precision reveals critical differences in head dimensions. Specifically, for sizes like M8, M10, M12, and M20, the “Width Across Flats” (head size) of GB/T 5783 is slightly smaller than DIN 933. These differences are often imperceptible to the naked eye but can be verified using precision calipers. For high-precision machinery, we always recommend adhering strictly to the specified standard to ensure tool fitment and torque consistency.

Product Classes and Accuracy: Grade A, B, and C

The selection of a hex bolt often depends on the required assembly precision. DIN 933 fasteners are categorized into three distinct grades:

• Class A and B: These represent high-precision machining. Class A is typically used for sizes up to M24 and lengths not exceeding 10D or 150mm. They offer tight tolerances and are essential for aerospace or high-speed machinery.
• Class C: This is the most common industrial grade. While it has a rougher finish and looser tolerances, it is cost-effective and perfectly suited for general construction and railway applications where extreme fitment precision is secondary to structural strength.

Technical Specifications: Standard Metrics for DIN 933

Engineering accuracy starts with knowing your dimensions. Below is a detailed breakdown of the technical data for preferred DIN 933 sizes produced by Ever Power:

Small Diameter Range (M4 to M6)

For M4, the standard pitch is 0.7mm. The head height (A) ranges from 2.62mm (Min) to 3.0mm (Max), with a width across flats (D) of approximately 7.0mm. Standard lengths range from 8mm to 40mm.

For M5, the pitch is 0.8mm. The head height is between 3.26mm and 3.74mm, with a head width of 8.0mm. Lengths vary from 8mm to 65mm.

For M6, the standard pitch is 1.0mm. The head height is 3.76mm to 4.24mm, and the width across flats is 10.0mm. Lengths are available from 10mm to 150mm.

Standard Industrial Range (M8 to M12)

For M8, the pitch is 1.25mm. Head height ranges from 5.06mm to 5.54mm, with a width across flats of 13.0mm. Standard lengths are 12mm to 200mm.

For M10, the pitch is 1.5mm. The head height is 6.11mm to 6.69mm, and the width across flats is 17.0mm. Lengths are 16mm to 200mm.

For M12, the pitch is 1.75mm. Head height ranges from 7.21mm to 7.79mm, with a width across flats of 19.0mm. Available lengths range from 20mm to 200mm.

Heavy-Duty Range (M14 to M22)

For M14 and M16, both feature a 2.0mm pitch. M14 head heights are 8.51mm to 9.09mm (22mm width), while M16 heights are 9.71mm to 10.29mm (24mm width). Both support lengths up to 200mm.

For M18, M20, and M22, the standard pitch is 2.5mm. Width across flats scales from 27mm (M18) to 30mm (M20) and 32mm (M22). Head heights for M20, for example, sit between 12.15mm and 12.85mm.

Material Science: The Chemical Integrity of SUS304 and SUS316

At Ever Power, our hex bolts are primarily manufactured in stainless steel to offer superior corrosion resistance. Choosing between 304 and 316 depends on your exposure environment.

SUS304 Stainless Steel (The Versatile Standard)

Known for its excellent cost-to-performance ratio, SUS304 contains Carbon (≤0.08%), Manganese (≤2.00%), Silicon (≤1.00%), Phosphorus (≤0.045%), and Sulfur (≤0.03%). Its strength and rust resistance come from its high Chromium (17.00% – 19.00%) and Nickel (8.00% – 11.00%) content.

SUS316 Stainless Steel (The Marine Choice)

For environments involving chlorides or sea spray, SUS316 is the definitive choice. While it maintains similar Carbon and Manganese levels as 304, it increases Nickel content (10.00% – 14.00%) and, most importantly, adds 2.00% – 3.00% Molybdenum (Mo). This addition provides exceptional resistance to pitting and crevice corrosion.

Thread Logic: Coarse vs. Fine

While DIN 933 defaults to Benang Kasar due to their high root strength and ease of assembly, fine threads are available for applications requiring high-precision adjustment or resistance to vibration-induced loosening. Coarse threads are the industry favorite for general construction and heavy industrial machinery.