Automatic Shot Blasting Machine for Tube & Pipe

The Automatic Shot Blasting Machine for Tube & Pipe by Finishree Equipment’s Pvt. Ltd. is a state-of-the-art, high-production surface preparation system engineered specifically for the continuous external descaling, rust removal, oxide elimination, and surface profiling of steel pipes, structural tubes, boiler tubes, casing pipes, and cylindrical rods.

Utilizing an advanced skew roller conveyor mechanism (conical diabolo rollers), the machine simultaneously rotates and advances the pipes through a heavy-duty, fully enclosed blast cabinet. High-efficiency blast wheels fire abrasives at high velocity across the entire perimeter, delivering 100% uniform 360-degree cleaning coverage, eliminating blind angles, and achieving clean surface finishes compliant with international SA 2.5 and SA 3.0 (ISO 8501-1) standards.

Working Principle & Operational Process

The automatic tube & pipe shot blasting process operates in a seamless continuous cycle designed for maximum productivity and safety:

1. Infeed & Skew Roller Conveyance:
Pipes are placed onto the entry skew roller conveyor bed. The angled conical diabolo rollers drive the pipe forward linearly while imparting smooth, continuous axial rotation. The speed is variable and regulated via a Variable Frequency Drive (VFD) to match required cleaning intensity.

2. Multi-Wheel High-Velocity Blasting:
As the rotating pipe enters the main blast enclosure, it passes directly through the intersecting blast streams of high-efficiency centrifugal blast wheels (turbines). The wheels throw abrasive media (cast steel shots or steel grit) at speeds exceeding 75–80 m/s, rapidly stripping stubborn mill scale, heavy corrosion, weld slag, and old paint coatings.

3. Manganese Armor Blast Enclosure:
The blast chamber is protected with replaceable 11–14% high-manganese cast alloy (Mn13) liners that resist abrasive wear. Multi-tier flexible rubber curtains at both inlet and exit vestibules effectively trap bouncing media, preventing shot spillage into the plant floor.

4. Automatic Media Circulation & Air-Wash Separation:
Spent abrasive media, dislodged rust, and scale drop into the hopper under the cabinet. A longitudinal screw conveyor feeds the material into a heavy-duty vertical bucket elevator, which lifts it into an advanced rotary screen and Air-Wash Separator. Usable steel shots are segregated from broken dust/fines and channeled back into the active storage hopper for continuous re-use.

5. Continuous Dust Extraction:
An industrial reverse pulse-jet cartridge/bag-type dust collector keeps the entire system under negative air pressure, continuously extracting airborne fines and dust to maintain clear internal visibility and provide an eco-friendly working atmosphere.

6. High-Pressure Air Blow-Off & Clean Exit:
Prior to exiting the discharge vestibule, automated high-pressure air blow-off nozzles dislodge any remaining abrasive media resting on the pipe surface, ensuring clean, ready-to-coat pipes exit onto the unload collection rack.

Key Machine Components

• Heavy-Duty Blast Cabinet: Fabricated from robust structural steel plates with full-coverage replaceable Mn13 manganese wear liners in direct blast zones.
• Skew Roller / Diabolo Conveyor: Angled polyurethane or hardened alloy steel diabolo rollers ensuring synchronized linear traverse and circumferential pipe rotation.
• High-Efficiency Blast Wheels: Dynamically balanced bi-directional centrifugal blast turbines equipped with high-chrome alloy impellers, control cages, and blades.
• Multi-Stage Air-Wash Abrasive Separator: Ensures only clean, correctly sized abrasive media is circulated back to the blast wheels, optimizing blasting speed and blade life.
• Heavy-Duty Bucket Elevator: Centrifugal discharge type equipped with high-tensile rubber belting, deep pressed steel buckets, and anti-slip drive pulleys.
• Automatic Pulse-Jet Dust Collector: High-capacity filtration unit with automatic reverse jet cleaning mechanism, ensuring dust emission levels below 10 mg/Nm³.
• Abrasive Blow-Off Unit: High-pressure blowers remove residual shot particles from pipe surfaces before workpieces leave the discharge tunnel.
• Centralized Electrical Control Panel: IP55 enclosure with PLC automation, intuitive touch HMI, digital speed readouts, and comprehensive emergency safety interlocks.

Industrial Applications & Uses

Automatic shot blasting machines for tubes and pipes are fundamental to operations across major heavy engineering sectors:

• Oil & Gas Transmission Pipelines: Essential surface preparation of steel line pipes prior to 3-Layer Polyethylene (3LPE), 3LPP, Fusion Bonded Epoxy (FBE), or coal tar enamel coatings.
• Water Supply & Sewage Pipelines: Descaling internal and external surfaces of carbon steel and ductile iron pipes before liquid epoxy coating, cement-mortar lining, or bituminous painting.
• Boiler & Heat Exchanger Manufacturing: Elimination of oxide scales and drawing lubricants from high-pressure boiler tubing to prevent premature localized thermal stress failure.
• Seamless & Welded Pipe Mills: Continuous inline descaling of ERW, LSAW, and SSAW pipes directly following welding and straightening operations.
• Automotive & Commercial Vehicles: Surface finishing of drive shafts, propeller shafts, hydraulic cylinder tubes, axle tubes, and exhaust components.
• Scaffolding & Structural Tubes: Rust and paint removal from reusable scaffolding pipes, circular hollow sections (CHS), and architectural pipe trusses.
• Gas Cylinders & Pressure Vessels: Surface etching of CNG, LPG, and industrial oxygen cylinder shells prior to primer and powder coating.

Abrasive Media Recommendations & Anchor Profile

The selection of abrasive media governs surface roughness, blast cycle time, and coating adhesion:

Cast Steel Shots (S-280, S-330, S-390): Spherical shots provide aggressive descaling while inducing beneficial compressive residual stress (peening action) that improves fatigue strength and creates a smooth peened finish.
Cast Steel Grit (G-25, G-40, G-50): Angular grit cuts quickly into stubborn heat-treat scale and mill scale, producing sharp microscopic peaks and valleys (anchor pattern of 40–80 µm) essential for high-integrity bonding of anti-corrosion barrier coatings (3LPE / FBE).
Operating Mix: Finishree recommends a balanced mix of 70% steel shots and 30% steel grit for optimal cleaning speed combined with superior anchor profile.