Lower Roll Bank for Straighteners and Levelers

Product Specifications

Technical details and manufacturing context for Lower Roll Bank

Definition

The Lower Roll Bank is a critical component of straightener and leveler machines, consisting of multiple parallel rolls arranged horizontally in the lower section of the machine. It works in conjunction with the upper roll bank to apply controlled pressure and bending forces to metal sheets, strips, or plates, removing distortions, waves, and residual stresses to achieve precise flatness and dimensional accuracy in manufactured metal products. The lower rolls provide a stable, rigid foundation against which the upper rolls apply downward pressure. As material passes between the upper and lower rolls, the lower rolls support the material while the upper rolls create controlled deflection patterns. The arrangement, diameter, and spacing of the lower rolls determine the bending moment applied to the material, with closer spacing providing more aggressive flattening for thicker materials and wider spacing for thinner materials. The Lower Roll Bank is typically made from alloy steel, tool steel, or hardened steel, with roll diameters ranging from 80 to 200 mm and face widths from 600 to 2500 mm. The number of rolls varies from 5 to 11, depending on the required flatness and cost considerations. Roller material hardness is specified as HRC 50–62, surface roughness as Ra 0.2–0.8 μm, and runout as ≤0.02 mm. The maximum material thickness handled is 0.5–6.0 mm, with a maximum material yield strength of ≤800 MPa. The operating temperature range is -10 to 60°C. Roller material grades include GCr15 for high hardness and 42CrMo for toughness, per GB/T 18254. The weight of the Lower Roll Bank ranges from 500 to 3000 kg, affecting installation and foundation requirements. These values are reference ranges and must be verified for the specific model and application with the legal manufacturer or supplier. Standards such as GB/T 230.1, GB/T 1031, GB/T 1184 are referenced for hardness, roughness, runout, and pressure testing, respectively, but do not imply certification or compliance of any specific product.

Working Principle

The Lower Roll Bank operates by providing a stable, rigid foundation against which the upper roll bank applies downward pressure. As material passes between the upper and lower rolls, the lower rolls support the material while the upper rolls create controlled deflection patterns. The arrangement, diameter, and spacing of the lower rolls determine the bending moment applied to the material, with closer spacing providing more aggressive flattening for thicker materials and wider spacing for thinner materials.

Common Materials

Alloy Steel, Tool Steel, Hardened Steel

Technical Parameters

Parameter	Typical range	Notes & selection driver
Roll Diameter	80–200 mm	Determines contact area and flattening force.
Roll Face Width	600–2500 mm	Must match material width.
Number of Rolls	5–11 pcs	More rolls improve flatness but increase cost.
Roller Material Hardness	HRC 50–62 HRC	Higher hardness improves wear resistance.GB/T 230.1
Roller Surface Roughness	Ra 0.2–0.8 μm	Affects material surface finish.GB/T 1031
Roller Runout	≤0.02 mm	Critical for uniform flattening.GB/T 1184
Max. Material Thickness	0.5–6.0 mm	Thicker material requires higher pressure.
Max. Material Yield Strength	≤800 MPa	Higher strength may damage rolls.
Operating Temperature	-10–60 °C	Outside range affects lubrication and material properties.
Roller Material Grade	GCr15 / 42CrMo	GCr15 for high hardness, 42CrMo for toughness.GB/T 18254
Weight	500–3000 kg	Affects installation and foundation requirements.

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

Components / BOM

Roll Shaft Part
Provides structural support and rotational axis for the roll

Material: Alloy Steel
Roll Shell Part
Outer cylindrical surface that contacts the material being processed

Material: Hardened Tool Steel
Roll Bearing Part
Supports rotational movement and handles radial/axial loads

Material: Bearing Steel
Bearing Housing Part
Secures bearings to the machine frame and maintains alignment

Material: Cast Iron or Steel
Adjustment Mechanism
Allows vertical positioning of individual rolls for crown control

Material: Steel

Application & selection

Application Fit & Sizing Matrix

Operational Limits

pressure:	Up to 2000 kN per roll, system dependent
other spec:	Roll surface speed: 5-150 m/min, Material thickness range: 0.3-25 mm
temperature:	Ambient to 150°C (302°F) typical; consult for higher temperatures

Media Compatibility

✓ Cold rolled steel ✓ Aluminum alloys ✓ Stainless steel

Unsuitable: Highly abrasive slurries or corrosive chemical baths

Sizing Data Required

Material yield strength and thickness
Required flatness tolerance (I-units or mm/m)
Production line speed (m/min)

Risk, maintenance & compliance

Reliability & Engineering Risk Analysis

Failure Mode & Root Cause

Bearing fatigue and spalling

Cause: Cyclic loading from material processing, inadequate lubrication, or contamination ingress leading to surface degradation and eventual bearing failure.

Roll surface wear and scoring

Cause: Abrasive particles in processed material, misalignment causing uneven contact, or insufficient roll hardness leading to progressive material loss and surface damage.

Maintenance Indicators

Abnormal vibration or audible knocking during operation indicating bearing or alignment issues
Visible scoring, pitting, or uneven wear patterns on roll surfaces during inspection

Engineering Tips

Implement precision laser alignment during installation and periodic checks to ensure optimal roll positioning and load distribution
Establish a proactive lubrication management program with filtered lubricants and scheduled oil analysis to monitor contamination levels

Indicative industry ranges for design and RFQ preparation. Confirm the exact figures and applicable standard with the manufacturer before specifying.

Compliance & Manufacturing Standards

Applicable Standards

ANSI B11.0 Safety of Machinery DIN 5510-2 Fire Behaviour of Materials

Quoted from the published standard.

Manufacturing Precision

Bore Diameter: +/-0.02mm
Surface Flatness: 0.1mm per meter

Quality Inspection

Dimensional Verification with CMM
Ultrasonic Testing for Internal Defects

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

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Inspection readiness

Confirm test methods, calibrated equipment, sampling plans, and traceable reports.

Supplier transparency

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Manufacturers of Lower Roll Bank

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Frequently Asked Questions

What materials are used for the Lower Roll Bank?

The Lower Roll Bank is typically made from alloy steel, tool steel, or hardened steel. Specific material grades include GCr15 for high hardness and 42CrMo for toughness, as referenced in GB/T 18254. The choice depends on the required hardness and toughness for the application.

What are the typical dimensions and specifications?

Reference ranges include roll diameter of 80–200 mm, face width of 600–2500 mm, number of rolls 5–11, hardness HRC 50–62, surface roughness Ra 0.2–0.8 μm, runout ≤0.02 mm, max material thickness 0.5–6.0 mm, max yield strength ≤800 MPa, operating temperature -10 to 60°C, and weight 500–3000 kg. These are directory references and must be confirmed for the specific model.

How does the Lower Roll Bank affect material flatness?

The Lower Roll Bank provides the lower support and contributes to the bending forces applied to the material. The number of rolls, their diameter, and spacing determine the bending moment. Closer spacing provides more aggressive flattening for thicker materials, while wider spacing is used for thinner materials. Proper configuration is critical for achieving precise flatness.

What standards are referenced for the Lower Roll Bank?

Standards referenced in the directory include GB/T 230.1 for hardness testing, GB/T 1031 for surface roughness, GB/T 1184 for runout, and testing. These are verification references and do not imply certification or compliance of any specific product. Always verify with the manufacturer.

Related equipment

Applied To / Applications

This component is essential for the following industrial systems and equipment:

Straightener / Leveler

View system integration details

Industrial Ecosystem & Supply Chain Structure

Complementary Systems

Downstream Applications

Specialized Tooling

Data Basis

Editorial classification, named public sources where available, and source-reviewed manufacturer records.

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.

Compiled and source-reviewed by the CNFX editorial team. Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review · Page last updated 12 October 2026

Lower Roll Bank