03 Bridges, Rail & Transport
Repeated load changes the specification.
JOTAIN can support material and processed-component routes for tension, anchorage, bolting, bearing-pin, and shaft-blank applications when the purchaser defines fatigue, fracture, temperature, geometry, and inspection requirements.
Component catalogue / 01
Where we can enter the supply route
Start with the component, then define the material condition, processing boundary, inspection plan, and documentary release.
Hanger and tension bars
High-strength rod material and drawing-defined end preparation for repeated-load applications.
- Heat-treated bar
- Thread or end preparation
- Dimensional inspection
Anchor rods
Bar and prepared threaded material for purchaser-designed infrastructure anchorage.
- Specified grade
- Cut length
- Protection when specified
Bearing pins and shaft blanks
Tough, machinable blanks for articulated and rotating interfaces.
- QT bar
- Rough machining
- UT when specified
High-strength fastener bar
Alloy bar route for purchaser-specified structural fasteners.
- Material route
- Heat treatment
- Machining allowance
Engineering conditions / 02
Define the service before the grade
The candidate route becomes meaningful only after load, environment, geometry, interfaces, and acceptance criteria are controlled.
Fatigue and fracture
Repeated-load details require more than a static strength target.
- Fatigue category
- Load spectrum
- Fracture toughness and service temperature
Connections
Bolted and pinned interfaces depend on installation and fit.
- Pretension or slip-critical intent
- Pin and bore tolerance
- Surface and assembly condition
Lifecycle
Inspection access and corrosion protection affect the supply route.
- NDT scope
- Protection system
- Inspectability and replacement strategy
Material route / 03
Material selection boundary
Candidate alloy-steel routes are assessed against section size, fatigue and fracture inputs, machinability, condition, and the asset owner's specification.
| Grade | Condition | Why it enters review | Application guardrail |
|---|---|---|---|
| 42CrMo4 / 4140 | QT or rough-machined | Candidate route for high-load pins, rods, and shaft blanks. | Fatigue and fracture acceptance remain project-specific. |
| 34CrNiMo6 | QT or forged route | Higher-hardenability route for heavy sections requiring toughness review. | Use only where the approved material specification permits it. |
| 35CrMo | QT or fastener-bar route | Candidate material for drawing-defined threaded and fastener components. | Connection-system compliance is not implied by material supply. |
Processing sequence / 04
A route that can be inspected
- 01Approved bar route
- 02Heat treatment
- 03Peeling or rough machining
- 04Thread or pin preparation
- 05Specified NDT and dimensions
- 06Protection and packing
Verification / 05
Evidence travels with the route
Define test location, acceptance criteria, inspection timing, marking, and release records before production.
Material
- Heat identity
- Mechanical properties
- Impact testing when specified
Integrity
- UT or other specified NDT
- Surface inspection
- Acceptance basis stated on order
Geometry
- Diameter and straightness
- Thread or pin dimensions
- Machining allowance
Standards context / 06
Reference the rule set—do not imply approval
The purchaser's approved drawing, project specification, inspection and test plan, and contractual standard editions control the order.
EN 1993 bridge fatigue context
Steel-bridge and fatigue design context; the asset-owner specification controls procurement.
Open reference ↗RCSC high-strength bolted joints
Design, installation, and inspection context for structural joints using high-strength bolts.
Open reference ↗FHWA steel bridges
US bridge fatigue, fracture, fastener, inspection, and quality reference context.
Open reference ↗Technical enquiry / 07
Send an enquiry engineering can review.
Include these inputs to reduce assumptions, shorten technical clarification, and keep the proposed route inside the purchaser's design boundary.
- 01Component and asset type
- 02Drawing and authority specification
- 03Load and fatigue context
- 04Grade or approved material
- 05Diameter, length, and allowance
- 06Delivery condition
- 07Impact and NDT requirements
- 08Connection or thread details
- 09Protection system
- 10Quantity and destination