HG508 Tube making machine for share Moulds

1. Overview

The HG508 Tube Making Machine is a high-frequency welded pipe production unit designed to manufacture steel tubes with an outer diameter up to 508 mm. The suffix "for Share Moulds" specifies a tooling strategy in which a single mould set is engineered to serve multiple tube diameters within a defined size group, rather than requiring one independent mould per diameter. This configuration is applied in production environments where a wide product range must be accommodated while keeping tooling inventory and procurement costs at a manageable level.

Yangzhou SINOFORM Machinery Co., Ltd., founded in 2010 and based in Yangzhou, Jiangsu Province, specializes in the manufacture of welded pipe units and rolling mill molds. The HG508 share mould line represents the upper end of the standard welded pipe machine range offered by the company and is directed at producers working with large-diameter structural and industrial tubing.

2. Key Technical Parameters

The table below presents the general technical scope of the HG508 tube making machine operating with shared mould tooling. Values are indicative and subject to project-specific engineering confirmation.

3. The Share Mould Concept

In tube mill terminology, moulds (also referred to as roll tooling or forming dies) are the shaped components mounted on the roll stands that progressively form, weld, and size the steel strip into finished tube. In a dedicated mould system, every target diameter requires its own matched mould set across the forming, squeeze, and sizing passes. For a machine capable of producing the full HG508 diameter range, this would mean procuring and storing a large number of distinct mould sets.

The share mould approach addresses this by partitioning the full diameter range into groups and engineering one mould set to cover all diameters within each group. This is made possible through:

• Calculated mould profiles that are contoured to accept the range of strip widths and forming radii within the group, without inducing unacceptable edge wave or weld seam offset.
• Adjustable stand geometry with horizontal gap and vertical pass-line settings that are repositioned when transitioning between sizes within the same group.
• Standardized shaft and housing interfaces so that the same mould body mounts directly across all stands in the group without adapters or spacers.
• Defined process parameter tables specifying stand settings, squeeze pressure, and HF power level for each diameter within the group, allowing repeatable setup on size changeover.

It should be noted that switching between diameter groups still requires a physical mould change. The share mould benefit applies to size changes within one group, where only stand repositioning is needed. For changes crossing a group boundary, the mould set must be replaced, though the total number of sets to manage remains significantly lower than in a fully dedicated tooling arrangement.

4. Dedicated Moulds vs. Share Moulds: Comparison

5. Machine Line Composition

5.1 Uncoiling and Edge Preparation

A heavy-duty hydraulic uncoiler supports large-weight coils appropriate for the strip widths used in 508 mm diameter production. An edge milling or strip-end shearing unit prepares the strip edges to specified geometry and removes oxide scale, which directly affects weld seam quality at large diameters.

5.2 Forming Section

The strip passes through multiple breakdown and fin-pass roll stands fitted with the share moulds for the applicable diameter group. Due to the large diameter range, the forming section of an HG508 line typically requires more pass stages than smaller-diameter mills, to achieve uniform forming without overstressing the strip material.

5.3 High-Frequency Induction Welding

At the welding station, HF induction coils heat the open tube edges to forging temperature. Squeeze rolls apply radial pressure to close the seam and consolidate the weld. For HG508-class diameters, welding power requirements are substantially higher than for smaller mills; the power unit must be sized to match the maximum wall thickness and target line speed. An internal and external scarfing assembly removes the weld bead to the required surface profile.

5.4 Sizing and Straightening

Downstream sizing stands fitted with the shared sizing moulds correct the outer diameter and roundness to final tolerance. A multi-roll straightener removes longitudinal bow. At large diameters, straightening force requirements are significant, and the straightener must be dimensioned accordingly.

5.5 Cut-Off and Run-Out

A flying saw or band saw cut-off machine cuts the tube to length while the line remains in motion. The run-out table collects finished tubes, which may then proceed to end-facing, hydrostatic testing, or marking depending on the applicable product standard.

6. Application Fields

Large-diameter tubes produced on the HG508 line are used in sectors that require substantial structural or conveyance capacity:

• Structural construction: columns, piles, and primary frame members in industrial buildings, bridges, and port infrastructure.
• Energy sector: casing, line pipe, and support structures for power generation and distribution facilities.
• Fluid and gas conveyance: large-bore pipelines for water supply, drainage, and low-to-medium pressure process piping.
• Mechanical engineering: heavy equipment frames, crane booms, and large-diameter conveyor and roller systems.
• Agricultural and civil infrastructure: irrigation main lines and culvert pipe applications.

7. Mould Design and Supply

SINOFORM manufactures both the HG508 tube making machine and the associated rolling mill moulds as integrated products. For the share mould system, the mould profile calculations are developed in conjunction with the machine design, ensuring that the stand geometry and the mould contour are matched throughout the full diameter group range.

Mould material selection for HG508-scale production considers the elevated forming forces involved at large diameters and heavier wall thicknesses. Common mould materials include forged alloy tool steel with appropriate heat treatment and high-chromium cast iron for applications requiring extended wear life. Replacement mould sets and re-grinding services for existing moulds are available as part of after-sales support.

8. Frequently Asked Questions