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8S Hex Nut Chinese Supplier
QS Fastener: 8S Hex Nut Chinese Supplier
Name: 8S Hex Nut Chinese Supplier
Standard: ASME B18.2.4.1M
Material: A193 Gr. 8S
Size: M12
Surface: Natural color
Price: USD 25 - 45/ Kg
MOQ: 10kg
Customization: yes
Delivery time: 7-30 Day
Standard: ASME B18.2.4.1M
Material: A193 Gr. 8S
Size: M12
Surface: Natural color
Price: USD 25 - 45/ Kg
MOQ: 10kg
Customization: yes
Delivery time: 7-30 Day
Quantity
This ASME B18.2.4.1M 8S Hex Nut is engineered for demanding bolted connections where vibration, medium-high temperature, and repeated disassembly challenge ordinary stainless fasteners. Manufactured from A193 Gr. 8S (UNS S21800 / Nitronic 60) alloy steel, it delivers tensile strength ≥860 MPa and sustained service up to 450 °C. The natural-color finish eliminates plating residue risks, while 500 h salt-spray testing shows no red rust. Common applications include petrochemical valves, pressure vessels, wind-tower flanges, and heavy-duty pump casings.
What sets grade 8S apart from other A193 grades? Unlike 8A (304-type), 8B (347 with Nb), or 8C (316 with Mo), 8S uses a manganese‑nitrogen formulation that boosts yield strength by 50–80 % over solution-treated 304/316, and cold-threading raises surface hardness above 250 HV – cutting galling risk to roughly one‑quarter that of 316. It retains 70 % of room‑temperature strength at 315 °C, versus 55–60 % for ordinary grades. Its PREN of ~21 is lower than 316’s 26, so it is not the first choice for long-term seawater immersion; however, its harder nitride film resists fretting plus crevice attack better than 316 in fluctuating loads.
Cost-wise, 8S bar stock runs about 2.2× 304 and 1.6× 316, but field data show a single galling-related pump pull‑out can cost 100 times the nut set. That is why many plant engineers call it the “insurance nut.” For example, an offshore water‑injection pump switched from B8M to this 8S Hex Nut and recorded zero galling over four openings in two years, saving 36 offshore hours and USD 1.2 M in lost output. A power‑plant turbine flange at 250 °C eliminated coated B16 nuts and dry-disassembly issues, cutting preload loss by 25 %. High‑speed train gear‑box covers using this nut with matching bolts survived six years without replacement, reducing maintenance man‑hours by 70 %.
Bottom line: high chloride → choose 8C/8M; frequent disassembly + galling worry + medium‑high temp vibration → choose this 8S Hex Nut. When you need a non‑magnetic, lubricant‑free locking solution that tolerates repeated torque, this is the most reliable safety fastener you can specify. For global projects, partnering with a reliable Chinese Supplier ensures competitive lead times (7–30 days), flexible MOQ (10 kg), and custom dimensions – all while meeting ASME B18.2.4.1M exactly. Whether you are retrofitting existing flanges or designing new skids, this 8S Hex Nut from a qualified Chinese Supplier offers the best balance of performance, availability, and cost‑effectiveness for critical service.
FAQ
1. Can I use the 8S Hex Nut in marine environments with high chloride?
It has a PREN of ~21, lower than 316, so for permanent seawater immersion we recommend 8C/8M; however, for splash zones or intermittent chloride exposure with vibration, 8S outperforms 316 due to its superior fretting and galling resistance.
It has a PREN of ~21, lower than 316, so for permanent seawater immersion we recommend 8C/8M; however, for splash zones or intermittent chloride exposure with vibration, 8S outperforms 316 due to its superior fretting and galling resistance.
2. Does the 8S Hex Nut require lubrication during assembly?
No – its natural finish and high surface hardness reduce galling so effectively that dry assembly is standard. This is particularly beneficial in high‑temperature or clean‑service applications where lubricants are prohibited.
No – its natural finish and high surface hardness reduce galling so effectively that dry assembly is standard. This is particularly beneficial in high‑temperature or clean‑service applications where lubricants are prohibited.
3. What is the minimum order quantity from a Chinese Supplier for this nut?
Most qualified suppliers offer an MOQ of 10 kg for standard M12 sizes, with customization available. Lead times typically range from 7 to 30 days depending on order volume and surface treatment requirements.
Most qualified suppliers offer an MOQ of 10 kg for standard M12 sizes, with customization available. Lead times typically range from 7 to 30 days depending on order volume and surface treatment requirements.
4. How do I distinguish genuine A193 Gr. 8S material from counterfeit alternatives?
Always request mill test reports confirming UNS S21800 chemistry and mechanical properties. A trusted Chinese Supplier will provide full traceability and third‑party inspection upon request.
Always request mill test reports confirming UNS S21800 chemistry and mechanical properties. A trusted Chinese Supplier will provide full traceability and third‑party inspection upon request.
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