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Allen Bolt China Supplier
QS Fastener: Allen Bolt China Supplier
Name: Allen Bolt China Supplier
Standard: ASTM
Material: A193 B7
Size: 3/8 to 1 Inch
Thread: 8 UN
Length: 30 to 800 mm
Grade: 10.9
Price: USD 2.25 - 6.99/ Kg
MOQ: 10kg
Customization: yes
Delivery time: 7-30 Day
Application: Oil Pipeline, Machinery, Chemical Industry, Building
Standard: ASTM
Material: A193 B7
Size: 3/8 to 1 Inch
Thread: 8 UN
Length: 30 to 800 mm
Grade: 10.9
Price: USD 2.25 - 6.99/ Kg
MOQ: 10kg
Customization: yes
Delivery time: 7-30 Day
Application: Oil Pipeline, Machinery, Chemical Industry, Building
Quantity
As a senior fastener engineer, I recognize that the reliability of critical connections often hinges on material selection and surface engineering. This Black Coated Allen Bolt, supplied by a professional China Supplier, is engineered to meet the rigorous demands of heavy industry. Manufactured in compliance with ASTM standards from A193 B7 alloy steel, these fasteners deliver the tensile strength and fatigue resistance essential for high-stress environments. The 10.9 strength grade—achieved through precise quenching and tempering—ensures consistent performance under dynamic and static loads, making this Allen Bolt a preferred choice for engineers worldwide.
Technical Specifications & Dimensional Versatility
Offered in diameters from 3/8 to 1 inch and lengths ranging 30 to 800 mm, with a unified 8 UN thread form, this Allen Bolt provides flexible fitment across various flange and machinery interfaces. The cold-headed and roll-threaded manufacturing process guarantees smooth flank surfaces and accurate pitch diameter, reducing the risk of galling during installation. With a competitive price of USD 2.25–6.99 per kg and a low MOQ of 10 kg, this China Supplier ensures cost-effective procurement without compromising quality. Custom lengths and special thread tolerances are available upon request, and the 7–30 day delivery window supports both urgent maintenance and scheduled project timelines.
Offered in diameters from 3/8 to 1 inch and lengths ranging 30 to 800 mm, with a unified 8 UN thread form, this Allen Bolt provides flexible fitment across various flange and machinery interfaces. The cold-headed and roll-threaded manufacturing process guarantees smooth flank surfaces and accurate pitch diameter, reducing the risk of galling during installation. With a competitive price of USD 2.25–6.99 per kg and a low MOQ of 10 kg, this China Supplier ensures cost-effective procurement without compromising quality. Custom lengths and special thread tolerances are available upon request, and the 7–30 day delivery window supports both urgent maintenance and scheduled project timelines.
Blackening Treatment Technology – Engineering Insights
The black oxide coating is not merely cosmetic; it is a functional barrier produced via high-temperature alkaline oxidation (135–150°C) in a NaOH+NaNO₂ bath. This thermochemical reaction generates a dense Fe₃O₄ magnetite film, approximately 1 μm thick—only 1/20 the thickness of zinc plating—thus preserving the original dimensional accuracy of the Allen Bolt thread. The process follows strict stages: alkaline degreasing, hydrochloric acid activation, and rinsing to ensure a pristine substrate. After 25±5 minutes of oxidation, the bolts undergo soaping (micropore sealing) and oil-immersion sealing, which enhances moderate corrosion resistance while imparting a uniform dark blue-black luster. Coating hardness (HV 50–100) is deliberately low to avoid hydrogen embrittlement, and adhesion to the base metal is excellent, preventing flaking under vibration.
The black oxide coating is not merely cosmetic; it is a functional barrier produced via high-temperature alkaline oxidation (135–150°C) in a NaOH+NaNO₂ bath. This thermochemical reaction generates a dense Fe₃O₄ magnetite film, approximately 1 μm thick—only 1/20 the thickness of zinc plating—thus preserving the original dimensional accuracy of the Allen Bolt thread. The process follows strict stages: alkaline degreasing, hydrochloric acid activation, and rinsing to ensure a pristine substrate. After 25±5 minutes of oxidation, the bolts undergo soaping (micropore sealing) and oil-immersion sealing, which enhances moderate corrosion resistance while imparting a uniform dark blue-black luster. Coating hardness (HV 50–100) is deliberately low to avoid hydrogen embrittlement, and adhesion to the base metal is excellent, preventing flaking under vibration.
Performance Characteristics & Application Scenarios
This Allen Bolt excels in oil pipeline flanges, heavy machinery frames, chemical reactors, and building structural joints—where environments are typically indoor or with relative humidity below 60%. For outdoor or marine exposure, supplementary topcoats are recommended. The blackening process is economical, with batch cycles under 2 hours and 65% lower chemical oxygen demand (COD) in wastewater compared to electroplating, aligning with modern sustainability goals.
This Allen Bolt excels in oil pipeline flanges, heavy machinery frames, chemical reactors, and building structural joints—where environments are typically indoor or with relative humidity below 60%. For outdoor or marine exposure, supplementary topcoats are recommended. The blackening process is economical, with batch cycles under 2 hours and 65% lower chemical oxygen demand (COD) in wastewater compared to electroplating, aligning with modern sustainability goals.
Conclusion
For engineers seeking a balance of strength, dimensional precision, and cost-efficiency, this Allen Bolt from a reliable China Supplier represents a sound specification. Its proven performance in petrochemical and mechanical applications, backed by customizable options and rapid supply, makes it a versatile fastening solution.
For engineers seeking a balance of strength, dimensional precision, and cost-efficiency, this Allen Bolt from a reliable China Supplier represents a sound specification. Its proven performance in petrochemical and mechanical applications, backed by customizable options and rapid supply, makes it a versatile fastening solution.
FAQ
Q1: Can this Allen Bolt be used in outdoor or humid environments?
A: It is best suited for indoor or dry conditions (RH<60%). For persistent moisture or salt spray, we recommend applying an additional rust-preventive topcoat or selecting a galvanized finish.
A: It is best suited for indoor or dry conditions (RH<60%). For persistent moisture or salt spray, we recommend applying an additional rust-preventive topcoat or selecting a galvanized finish.
Q2: What is the maximum tensile load for the 1-inch diameter size?
A: Based on the A193 B7 material and Grade 10.9 properties, the minimum tensile strength is approximately 1040 MPa. Actual working load depends on thread engagement and joint design—please refer to our engineering load charts.
A: Based on the A193 B7 material and Grade 10.9 properties, the minimum tensile strength is approximately 1040 MPa. Actual working load depends on thread engagement and joint design—please refer to our engineering load charts.
Q3: How does the black oxide coating affect thread fit and gauge inspection?
A: The coating thickness is only 0.5–1.5 μm, which does not alter the pitch diameter significantly. Standard thread plug and ring gauges remain applicable without adjustment.
A: The coating thickness is only 0.5–1.5 μm, which does not alter the pitch diameter significantly. Standard thread plug and ring gauges remain applicable without adjustment.
Q4: Are special lengths or non-standard threads available beyond the listed range?
A: Yes, as a flexible China Supplier, we offer custom lengths up to 1000 mm and alternative thread forms upon request. Please contact our technical team with your drawing for a feasibility review.
A: Yes, as a flexible China Supplier, we offer custom lengths up to 1000 mm and alternative thread forms upon request. Please contact our technical team with your drawing for a feasibility review.
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