SS Bolt And Nut

QS Fastener: SS Bolt And Nut

Name: SS Bolt And Nut
Size: 3/4 Inch
Length: 175mm
Application: For Installation of the Equipment in the Offshore Oil and Gas Production System
Material: ASTM A193 B8M CL.II
Feature: Strain Hardening

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SS Bolt And Nut is a high-performance stainless steel fastening solution specifically designed for offshore oil and gas production systems, manufactured from ASTM A193 B8M CL.II strain-hardened material. This SS Bolt And Nut combination achieves ultra-high strength and exceptional corrosion resistance with its 175mm custom length. Its salt spray and high-pressure certified hardening process ensures long-term reliability for critical components like drilling platform equipment and subsea pipelines under extreme operating conditions.

Manufacturing Process of SS Bolt And Nut
Bolt Forming Process
1. Multi-Station Cold Heading (Deformation ≤80%)
As the core process in SS Bolt And Nut manufacturing, cold heading performs plastic deformation of metal wire at room temperature.
- Material Preparation: Uses low-carbon or alloy steel wire (e.g., ML35, 40Cr) matching SS Bolt And Nut specifications. Wire requires pickling and phosphating for improved lubricity.

- Process Flow:
- Cutting: Wire sheared to predetermined length
- Pre-forming: Initial upsetting to create head chamfers/cones
- Final forming: 3-6 progressive dies form SS Bolt And Nut head (hex, round, etc.) and shank, controlling deformation below 80% to prevent cracking
- Diameter reduction (optional): Shank sizing for dimensional accuracy
- Advantages: >95% material utilization, high efficiency (up to 200pcs/min), continuous grain flow, superior strength vs machining

2. Thread Rolling (UNJ/ACME High-Precision Profiles)
SS Bolt And Nut employs thread rolling to enhance fatigue life and precision.
- Rolling Method: 2- or 3-die rolling machines with powder high-speed steel dies (e.g., ASP30, hardness ≥HRC60)
- UNJ Thread: Aerospace standard with large root radius (R=0.15011P), requiring controlled pressure to prevent crest collapse
- ACME Thread: 29° trapezoidal power threads needing dedicated rollers for flank angle accuracy (±0.5°)
- QC: Go/no-go gauge inspection (6g tolerance), surface roughness Ra≤1.6μm

Nut Forming Process
1. Hexagonal Hot Forging
For large-size (M12+) or high-strength SS Bolt And Nut nuts (Grade 10), using medium-carbon steel (e.g., 35K).
- Heating: Induction to 1100-1200°C (austenitic zone), minimizing exposure to prevent decarburization

- Forging:
- Pre-forging: Punch forms hexagonal outline
- Final forging: Closed-die precision forging, flash thickness ≤0.5mm

- Post-treatment: Trimming, shot blasting for scale removal, quenching+tempering to HRC28-32

2. Internal Thread Tapping (H2 Fit Class)
SS Bolt And Nut nuts require drilling before tapping, with H2 being medium fit (between H1-H3 tolerance).
- Drilling: Tap drill diameter = Major diameter - Pitch (e.g., M10×1.5: Ø8.5mm), perpendicularity ≤0.05/10mm
- Tapping:
- HSS taps (M2 grade), TiN-coated for extended life
- Cutting speed: Low-carbon steel 15-20m/min, alloy steel 5-10m/min
- Lubrication: EP cutting oil (sulfur-chlorine) to reduce galling
- Inspection: H2 thread plug gauges for pitch diameter tolerance (e.g., M10 H2: +0.038/+0.153mm)

Process Comparison & Synergy
- The difference between cold heading for bolts and hot forging for nuts in SS Bolt And Nut stems from size effects: cold heading suits small parts (low deformation resistance), while hot forging is for large parts requiring recrystallization temperature.
- Thread matching: SS Bolt And Nut's UNJ/ACME rolled threads must align with H2 tapped nuts, typically maintaining 0.1P (pitch) clearance.

This process chain balances efficiency and performance, making SS Bolt And Nut the preferred solution for high-strength fasteners in automotive, aerospace, and other critical applications.

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