Product Parameters
| Item | Specification |
|---|---|
| Major Diameter | 12 mm – 150 mm |
| Standards | ANSI B92.1, DIN 5480 |
| Material | 8620 Carburizing Steel, 4340 Alloy, 17-4 PH Stainless |
| Surface Hardness | 58–62 HRC |
| MOQ | 10 pcs |
description
Internal spline shafts show up in automotive transmissions, aerospace actuators, and hydraulic systems - anywhere torque has to get from one rotating component to another without slippage. The internal teeth mate with external splines, which means no keyway stress concentrations and better load distribution across the engagement. 8620 carburizing steel is the workhorse. The surface gets hard during heat treatment while the core stays ductile - good combination for handling shock loads without becoming brittle. 4340 gives you consistent properties through the cross-section, which matters for larger diameters. 17-4 PH stainless is for situations where rust is a real concern and strength still needs to be there.
Spline vs. Keyway - Why Splines Win for High Torque
A keyway removes about 20% of the shaft cross-section at the keyway location - significant stress concentration in a high-load area. Splines distribute torque across all teeth in engagement, so the shaft stays full-diameter. If your application is limited by shaft torque capacity, switching from keyway to splines can increase the torque rating substantially without changing shaft diameter.
FAQ
Q1: MOQ?
A1: 10 pieces.
Q2: Standards?
A2: ANSI B92.1 and DIN 5480. Custom configurations available.
Q3: Materials?
A3: 8620, 4340, 17-4 PH stainless. More available on request.
Q4: Hardness?
A4: 58–62 HRC on tooth surfaces, core stays ductile.
Q5: Heat treatment in-house?
A5: Yes - case-hardening, induction hardening, through-hardening.
Q6: Surface treatments?
A6: Manganese phosphate, black oxide, zinc plating, electroless nickel.
Quality is non-negotiable in precision manufacturing. Every component undergoes rigorous inspection at each stage of production.
- AS/EN/JISQ 9100 - Aerospace quality management for flight-critical and structural parts
- NADCAP - Accredited special processes including heat treatment, NDT, and surface treatment
- DFARS / ITAR - Compliant supply chain for defense and space applications
- Boeing DMS / Airbus SP - Customer-specific requirements documentation available
- Passivation / Electropolishing - ASTM A967 procedures for corrosion resistance
- Material Traceability - Heat number tracking from raw material to finished part
From raw material to finished product, every step is controlled and documented:
- Material Preparation - CNC turning/milling to near-net shape
- Heat Treatment - Through-hardening or case-hardening for strength-critical parts
- Surface Preparation - Degreasing, acid cleaning, and surface activation
- Electroplating - Controlled bath process with thickness monitoring
- Sealing / Baking - Chrome sealing, anodize sealing, or hydrogen embrittlement relief baking
- Inspection - Coating thickness measurement, adhesion testing, and visual check
- Packaging - Protective interleaving, VCI packaging, and anti-tarnish wrapping
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