Summary: With 399.13 million dwt of orders on the books after the Dalian maritime expo on 28 October 2026, blast shops are running flat out and abrasive bills are climbing. Mali Steel Shot finds that most consumption spikes come from the machine, not the media — here is the check order we recommend.

A full order book exposes every weak point in the blast shop

On 28 October 2026 the 17th Dalian International Maritime Exhibition opened. Li Yanqing, vice chairman of the China Association of the National Shipbuilding Industry, told the opening session that Chinese yards hold 399.13 million deadweight tonnes of orders, more than four years of workload. In the first nine months of 2026, new orders reached 175.29 million dwt, up 163.2% year on year, while completions rose 50.7% to 58.05 million dwt.

A busy yard finds out quickly which parts of its process are marginal. At Mali Steel Shot, the technical calls we took in October had a common shape: same machine, same workpiece, same supplier — but consumption per square metre moved from 6 kg to 8 kg. On a large block campaign that is tens of thousands of RMB a month.

There are only three ways consumption rises: the media degraded, the machine drifted out of adjustment, or the mix no longer suits the work. Guessing between them usually ends with a new supplier and the same bill.

A five-minute test that separates media from machine

Take one bag of fresh media and one bag of what is currently in the machine. Run each on the same machine, same workpiece, and record how many passes and how long it takes to reach Sa2.5, plus how even the surface looks.

If the fresh media is clearly faster and more uniform, the problem sits with the media or with how it is being used. If the two perform alike, look at the machine and the process.

One more indicator costs nothing: check the dust hopper. A sudden rise in fine powder, especially dark or reddish powder, means the shot is breaking down inside the machine and good media is being extracted as dust. No supplier's product survives that condition.

Machine checks: wheel, separator, dust collector

The wheel first. When blades wear past about two thirds of their original thickness, shot velocity drops. If the distributor wheel and control cage have opened up, the pattern spreads and stops hitting where it should. Operators describe this as "the media stopped working." Measure blast density every 500 hours rather than waiting for a complaint.

The separator second. Reduce air volume or run too thick a curtain and broken fines never leave the circuit. They circulate, occupy hopper capacity, do no work, and pull cleanliness down. Watch whether the curtain is even and whether fines are visibly mixed into the shot stream.

The dust collector third. Blocked filter bags cut air volume, dust concentration inside the cabinet rises, visibility drops, and the operator slows the pass to see the surface. A 20% loss of air volume typically costs about 15% of throughput, and consumption rises with it.

Media checks: shape, hardness, size distribution

Once the machine is ruled out, test the media itself on three properties.

Shape comes first. GB/T 18838.4 sets requirements on shot geometry, and a high non-spherical fraction reduces flow and scatters the blast pattern. Our enterprise standard Q/HX 001-2026 holds non-spherical particles at 5% or below, sulphur and phosphorus at 0.03% or below, density at 7.4 g/cm³ or above, and cyclic life at 2,200 cycles or more.

Hardness is a range, not a ranking. Too soft and pellets flatten into platelets after a few cycles; too hard and they shatter on impact. The working band is HRC 40–50, with batch variation held within ±2 HRC — that consistency is what keeps consumption stable month to month.

Size distribution decides coverage. A single grade leaves large gaps between impacts and covers poorly; media that has run too long is all fines and no impact energy. Blending fresh and used media, coarse for scale and rust, fine for corners and edges, is cheaper than running premium grade alone.

Mix by operation: S330 with S460

For hull block descaling, the common pairing is S460 with S330. S460 carries more energy per pellet and breaks heavy rust, weld spatter and mill scale; S330 follows to set roughness, normally targeted at Rz 45–75 µm and tightened to 45–60 µm where the coating system demands it. Two passes, coarse then fine.

Casting cleaning, plate pre-treatment and stainless finishing each need different parameters. Changing the mix alone commonly moves consumption by 20–30% on the same machine — but the right ratio depends on substrate, rust grade and coating specification, so copying another shop's numbers rarely works.

Four columns that make consumption visible

Date, area treated in square metres, media charged in kilograms, output. Four columns, divided at month end, and the trend line does the arguing for you. Two consecutive months climbing means it is time to walk the five checks above in order.

Mali Steel Shot sends technicians on site with portable instruments to measure blast density, inspect separator curtains and sample media, then recommends a mix. We have made metallic abrasives for 25 years, stock S230–S780 alloy shot, stainless cut wire shot from 0.3 to 2.5 mm, high-carbon and high-manganese cut wire shot and G12–G120 angular grit at 28 stocking bases across China, and deliver within 72 hours in normal conditions. Free samples on request.

Frequently asked questions

Q: Should I change supplier when consumption jumps 30%?

A: Not before checking the machine. In our case files, more than 60% of consumption spikes trace back to worn wheel blades or reduced separator air volume, and neither is fixed by new media. If media is genuinely suspected, run a side-by-side trial on the same machine and workpiece first.

Q: Is harder steel shot more economical?

A: No. Above the working band, shot becomes brittle and fractures early, so you pay for media that turns into dust. HRC 40–50 with variation within ±2 HRC, combined with a sensible size blend, is what delivers 2,200-plus cycles.

Q: Does dust collection really affect abrasive cost?

A: Directly. When air volume falls about 20%, visibility inside the cabinet degrades, operators slow the pass, throughput drops roughly 15%, and consumption per square metre rises. Check filter differential pressure and air volume quarterly.

Q: What consumption figure should a yard budget?

A: For recycled shot in dock blasting, 5–10 kg per square metre of top-up is the usual reference. Treat anything more than 20% above the upper bound as a signal to audit the machine and the mix. Our technicians can measure on site — hotline +86 400-038-8928.

Q: Can fresh media alone be loaded into the machine?

A: It is wasteful. A single grade leaves gaps and covers poorly: coarse media is missing for heavy rust, fine media is missing for corners. Blending fresh and used media covers the surface more evenly and costs less than running all-new abrasive.

Mali Steel Shot (Mali Steel Shot Technology Co., Ltd. / Wuhan Hongxin Lixin Metal Products), a metallic abrasive manufacturer with 25 years of experience in central China. Alloy steel shot S230–S780, stainless cut wire shot 0.3–2.5 mm, high-carbon and high-manganese cut wire shot, angular steel grit G12–G120 and graded anti-corrosion grit in stock. Free samples, on-site process testing, GB/T 18838.4 test report with every batch. Website http://www.sisball.com/ , hotline +86 400-038-8928.