Neck (Journal): Diameter tolerance h6/h7

Component Specifications

Definition

The neck or journal of a work roll is the cylindrical portion at each end of the roll that fits into bearings within the roll chocks. This critical component transmits torque from the drive system while supporting radial and axial loads during metal rolling operations. It maintains precise alignment and rotational stability under extreme mechanical stresses in hot/cold rolling mills.

Working Principle

The journal converts rotational drive torque into rolling force through bearing interfaces while maintaining geometric precision under load. It operates as a mechanical power transmission element that must withstand cyclic bending moments, torsional stresses, and thermal expansion differentials between the roll body and bearing assemblies.

Materials

Forged alloy steel (typically AISI 4340, DIN 34CrNiMo6) with surface hardening to 55-62 HRC. Chrome-molybdenum-nickel alloys provide fatigue resistance with core toughness. Precision grinding achieves surface finish Ra ≤ 0.4 μm.

Technical Parameters

Parameter	Typical range	Notes & selection driver
Core Hardness	28-32 HRC
Surface Finish	Ra 0.2-0.4 μm
Surface Hardness	58-62 HRC
Diameter Tolerance	h6/h7
Roundness Tolerance	≤ 0.01 mm
Straightness Tolerance	≤ 0.02 mm/m

Ranges are indicative industry figures for RFQ preparation, not a supplier commitment. Confirm every value and standard with the legal manufacturer before ordering.

Standards

ISO 286-2, DIN 7150, ASTM A29

Parent Products

This component is used in the following industrial products

Work Rolls

Primary rotating cylinders that directly contact and deform metal during rolling operations.

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Rolls (Work Rolls)

The primary rotating cylinders in a rolling mill that directly contact and deform the metal workpiece.

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Engineering Analysis

Risks & Mitigation

Bearing seizure due to lubrication failure
Fatigue cracking from cyclic loading
Geometric distortion under thermal stress
Corrosion in humid mill environments

FMEA Triads

Trigger: Inadequate lubrication flow
Failure: Journal overheating and bearing seizure
Mitigation: Install flow sensors with automatic shutdown triggers

Trigger: Bearing misalignment during installation
Failure: Accelerated wear and vibration
Mitigation: Implement laser alignment procedures with 0.05mm tolerance

Trigger: Thermal expansion mismatch
Failure: Crack initiation in journal fillet radius
Mitigation: Design with controlled cooling channels and thermal barriers

Industrial Ecosystem

Compatible With

Typical Suppliers & Equivalents

Compliance & Inspection

Tolerance

Geometric tolerances per ISO 2768-mK, dimensional per ISO 286-2

Test Method

Dimensional: CMM measurement; Hardness: Rockwell C scale; Surface: profilometer; NDT: magnetic particle inspection per ASTM E709

Procurement Evaluation Criteria

A practical evidence checklist for RFQ preparation and supplier evaluation.

Technical documentation

Request current drawings, revision history, and a signed specification sheet.

Manufacturing capability

Verify equipment lists, process limits, capacity, and representative production evidence.

Inspection readiness

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Manufacturers of Neck (Journal)

Manufacturer profiles associated with Neck (Journal).

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Shaft Bearing

Precision component supporting rotating shafts in vibration motors to reduce friction and maintain alignment.

Seal Groove

Precision-machined groove in aluminum bearing housings designed to accommodate sealing elements for fluid containment and contamination prevention.

Frequently Asked Questions

What causes journal scoring in work rolls?

Journal scoring typically results from lubricant failure, bearing misalignment, or contamination ingress. Preventive measures include proper lubrication systems, bearing clearance monitoring, and seal maintenance.

How often should roll journals be inspected?

Visual inspections should occur during roll changes (weekly-monthly), with dimensional checks every 3-6 months. Non-destructive testing (magnetic particle/ultrasonic) is recommended annually or after 10,000 operating hours.

Can damaged journals be repaired?

Minor scoring can be polished out if within tolerance limits. Severe damage requires metal deposition (welding/thermal spray) followed by precision regrinding, though replacement is often more economical for critical applications.

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records. See the editorial policy.

Preliminary Technical Classification

This page supports structured research, RFQ preparation, and supplier evaluation. It does not replace buyer-led supplier qualification, standards review, or technical approval.

Neck (Journal)