Medium-Strength Metric Class 8.8 Steel Thread-Locking Serrated-Flange Hex Head Screw

Material: Carbon steel.Alloy steel.40Cr alloy steel

Standard: GB 5789&Q 180&Q 181&Q 182&ISO 15072&ISO 4162 &DIN 6921&DIN 6922&ASME B 18.2.3.4M&JIS B 1189 (Type 2)

1.High-Strength Metric Class 10.9 Steel Flanged Hex Head Screws：Choose these Class 10.9 steel screws for high-stress applications, such as valves, pumps, motors, and automotive suspension systems. They are at least 25% stronger than medium-strength steel screws. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. Head height includes the flange. Length is measured from under the flange.

Black-phosphate steel screws are mildly corrosion resistant in dry environments. Zinc yellow-chromate plated steel screws resist corrosion in wet environments.

Screws that meet ISO 898-1 or SAE J1199 comply with specifications and testing requirements for material quality. Screws that meet ASME B18.2.3.9M or DIN 6921 comply with specifications for dimensional standards.

2.High-Strength Grade 8 Steel Flanged Hex Head Screws：Made from Grade 8 steel, these screws can be used in high-stress applications, such as valves, pumps, motors, and automotive suspension systems. They are at least 25% stronger than medium-strength steel screws. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. Material meets SAE J429 specifications for quality. Dimensions meet IFI 111 specifications. Grade 8 steel hex head screws are marked with six radial lines. Head height includes the flange. Length is measured from under the flange.

Black-phosphate steel screws are mildly corrosion resistant in dry environments. Zinc yellow-chromate plated steel screws resist corrosion in wet environments.

Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don’t know the threads per inch. Fine threads are closely spaced to prevent loosening from vibration.

3.JIS High-Strength Steel Flanged Hex Head Screws：Made to Japanese Industrial Standards, these Class 10.9 steel screws can be used in high-stress applications, such as valves, pumps, motors, and automotive suspension systems. They are at least 25% stronger than medium-strength steel screws. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. The zinc plating provides corrosion resistance in wet environments. Head height includes the flange. Length is measured from under the flange.

Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don’t know the pitch. Fine and extra-fine threads are closely spaced to prevent loosening from vibration; the finer the thread, the better the resistance.

4.Medium-Strength Metric Class 8.8 Steel Flanged Hex Head Screws：These Class 8.8 steel screws are suitable for fastening most machinery and equipment. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. All screws meet DIN 6921 specifications for dimensions. Head height includes the flange. Length is measured from under the flange.

Zinc yellow-chromate-plated screws resist corrosion in wet environments. They also meet ISO 898-1 specifications for materials. Black corrosion-resistant-coated screws resist chemicals and withstand 1,000 hours of salt spray. To maintain corrosion resistance, use these screws with black ultra-corrosion-resistant-coated nuts and washers.

5.Medium-Strength Grade 5 Steel Flanged Hex Head Screws：Made from Grade 5 steel, these screws are suitable for fastening most machinery and equipment. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. Material meets SAE J429 specifications for quality. Dimensions meet IFI 111 specifications. Grade 5 steel hex head screws are marked with three radial lines. Head height includes the flange. Length is measured from under the flange.

Zinc-plated steel screws resist corrosion in wet environments. Black corrosion-resistant-coated steel screws resist chemicals and withstand 1,000 hours of salt spray. To maintain corrosion resistance, use these screws with black ultra-corrosion-resistant-coated nuts and washers.

Match the thread spacing of mating components. Coarse threads are the industry standard; choose these screws if you don’t know the threads per inch. Fine threads are closely spaced to prevent loosening from vibration.

6.Extreme-Strength Steel Flanged Hex Head Screws：Comparable in strength to Grade 9 steel screws, these screws are about 20% stronger than high-strength steel flanged screws. Use them for heavy duty stamping applications as well as earth-moving machinery, such as bulldozers and excavators. The flange distributes pressure where the screw meets the surface, eliminating the need for a separate washer. The black-oxide finish provides mild corrosion resistance in dry environments. Head height includes the flange. Length is measured from under the flange.