The blackening process of blackened hexagonal bolts has the advantages of safety, no electricity, high efficiency, low cost, simple equipment, easy operation and strong process adaptability. The specific process is as follows:
2. Degreasing: the workpiece must be completely immersed in the degreasing solution; the concentration of the degreasing solution is 12-14, the treatment time is 10-30 minutes, shaking several times every 3-5 minutes, and adding degreasing powder when the concentration of the liquid is lower than pH 12
4. pickling: the pH value of pickling solution is 2-4, and the treatment time is 5-10 minutes.
6. blackening: the pH value of the pond liquid is 2.5-3.5, and the treatment time is 10-12 minutes
8. Blow dry
It should be noted that in practice, the quality of rust removal and oil removal before blackening of blackened hexagonal bolts, and passive oil soaking after blackening. The quality of blackening often varies with these processes.
ASTM A490 Hex Head Bolt
ASTM A490 Hex Head Bolt Standard: ISO, JIS, GB, ANSI, BSW, DIN or non standard as customize. Material: Carbon Steel, Stainless Steel, steel, aluminum,brass, titanium, Copper,etc Size: M2-M52 or non-standard as request & design Length: M10-M300 as request & design Grade: 4.8,6.8,8.8,10.9,12.9,A2-70,A4-80,etc Surface Treatment: Zn- Plated, Ni-plated, Passivated, Tin-plated, Sandblast and Anodize, Polish, Electron Painting,Black […]
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High Strength A490 Bolt Material: Carbon Steel, Stainless steel, Alloy Steel etc Size: M4-M100 1/4″-4″ Length: 6mm to 100mm Thread: UNC, UNF are available Surface Treatment: Black oxide, zinc plate, copper plating, Dacromet, Teflon, phosphating Certificate: ISO9001:2008, ROHS, SGS, CE Standard: DIN, ISO, ANSI, ASTM, ASME, GB, JIS After-sale: Solve all your problems satisfied after […]