PRODUCT

Stainless steel spherical shot

STAINLESS STEEL LINE · FERROUS-FREE

Metallic abrasive for blasting aluminium, stainless steel and non-ferrous metals

CYM Materiales supplies Chronital stainless steel spherical shot, a corrosion-resistant cast metallic abrasive, available in ten grades from S10 to S300. It is the correct technical choice for blasting aluminium, stainless steel, zinc, zamak and other non-ferrous metals, as well as for the stone and precast concrete industries, where the absence of ferrous contamination is a requirement.

Unlike carbon steel shot, stainless shot leaves no oxidizable particles on the treated part: it does not generate later rust spots or stains on polished, bright or painted surfaces. Its austenitic chromium-nickel composition provides corrosion resistance, while progressive hardening during operation —through cold work induced by impact— raises hardness from 275 HV at supply to 475 HV in the operating mix, delivering long media life and stable behavior.

Stainless shot is used for cleaning, deburring, finishing and surface preparation in aluminium casting and forging, zinc and zamak die-casting, stainless steel boilermaking, decorative blasting of natural stone and prestressed concrete, and removal of weld discoloration on stainless steel parts. It is virtually dust-free, delivers bright finishes and reduces consumption by 50 % to 85 % compared with mineral abrasives such as aluminium oxide or garnet.

If your application requires a specific recommendation, our technical team advises on the most suitable grade and composition — Chronital or Chronital 13.

APPLICATIONS

Uses and processes with stainless spherical shot

Chronital stainless steel spherical shot is used in processes that do not admit ferrous contamination or later oxidation on the treated part. It works by gentle impact without generating an aggressive profile, preserving the original dimensions and delivering a homogeneous, bright finish. It is used both in centrifugal wheel machines and in compressed air systems —pressure or suction— and grade selection depends on the material, the equipment and the required finish.

CENTRIFUGAL WHEEL BLASTING

Compatible with CYM Materiales wheel equipment for aluminium, stainless steel and non-ferrous parts
Suited to aluminium casting and forging on tumble belt, rotary table and satellite blast machines
Recommended for blasting aluminium profiles prior to anodizing, for its uniform finish and the absence of ferrous contamination that would affect the bath
Recommended for industrial mold cleaning (glass, aluminium extrusion, zinc/zamak die-casting) without altering the original dimensions
No ferrous contamination on parts that require complete absence of surface rust
Grades S100 to S300 for heavy casting and foundry sand removal
Stable operating mix with hardness increasing through work hardening during the process
Lower wear on blast wheels and nozzles than with mineral abrasives (aluminium oxide, garnet)

AIR BLASTING — PRESSURE AND SUCTION

Suited to blast cabinets, manual blast rooms and suction and pressure systems
Fine grades S10 to S60 for bright, decorative finishes and cleaning of delicate parts
Virtually dust-free: better visibility in manual blast rooms and lower environmental impact
Applications: stainless steel boilermaking, decorative blasting of granite and prestressed concrete, removal of weld discoloration on stainless parts
Reduces abrasive consumption by 50 % to 85 % compared with single-use mineral abrasives
Available in Chronital 13 composition (high-nickel) for critical applications requiring higher corrosion resistance

TECHNICAL SPECIFICATIONS

Manufacturing standard and chemical composition

Stainless steel spherical shot is manufactured as cast stainless steel shot, corrosion-resistant, in spherical form. CYM Materiales supplies two compositions according to the corrosion resistance required by the application: Chronital, with standard chromium-nickel, and Chronital 13, with higher nickel content for critical applications. Chemical composition is kept within the following ranges:

Element	Chronital	Chronital 13
Carbon (C)	0,14 – 0,18 %	0,14 – 0,18 %
Chromium (Cr)	17 – 19 %	17 – 19 %
Nickel (Ni)	8 – 10 %	~13 %
Silicon (Si)	≤ 1,8 %	≤ 1,8 %
Manganese (Mn)	≤ 1,2 %	≤ 1,2 %

Cast austenitic chromium-nickel stainless steel shot, corrosion-resistant. Composition aligned with the AISI 304 family (Chronital) and AISI 305/308 (Chronital 13). The difference between the two compositions lies in nickel content: Chronital 13 offers higher corrosion resistance in aggressive environments and greater austenitic phase stability during blasting. Unlike carbon steel shot, stainless shot does not follow SAE J-444: it is classified by chemical composition and by Chronital grades S10 to S300.

Metallurgical structure

Stainless shot has an austenitic structure with delta ferrite below 10 %, characteristic of chromium-nickel steel in the cast and cooled state. Unlike carbon steel shot, its hardness is not obtained by prior heat treatment: during blasting, continuous impact induces the transformation of austenite into martensite by cold deformation (work hardening), progressively hardening the particles as they enter the operating regime. This transformation is irreversible and stabilizes the operating mix: virgin shot delivers 275 HV (~28 HRC) at supply and reaches approximately 475 HV (~47 HRC) once in the work cycle, extending media life and maintaining stable behavior throughout operation.

Granulometry — Chronital grades S10 to S300

Stainless spherical shot is classified in ten grades by nominal grain size, in a nomenclature proper to the Chronital line (SAE J-444, used for carbon steel shot, does not apply). Each grade defines the sieve through which at least 90 % of the material must pass and a maximum 5 % limit on the next coarser sieve. CYM Materiales supplies the full range from S10 (fine shot for decorative finishes) to S300 (coarse shot for sand removal and foundry cleaning):

Code	Nominal sieve (mm)	Specification
S300	2.50	max 5 % in sieve 3.0 mm · min 90 % passes sieve 1.7 mm
S200	2.00	max 5 % in sieve 2.0 mm · min 90 % passes sieve 1.4 mm
S150	1.40	max 5 % in sieve 1.7 mm · min 90 % passes sieve 1.25 mm
S100	1.25	max 5 % in sieve 1.4 mm · min 90 % passes sieve 1.0 mm
S60	1.00	max 5 % in sieve 1.25 mm · min 90 % passes sieve 0.7 mm
S50	0.80	max 5 % in sieve 1.0 mm · min 90 % passes sieve 0.6 mm
S40	0.60	max 5 % in sieve 0.8 mm · min 90 % passes sieve 0.4 mm
S30	0.50	max 5 % in sieve 0.5 mm · min 90 % passes sieve 0.14 mm
S20	0.30	max 5 % in sieve 0.3 mm · min 90 % passes sieve 0.09 mm
S10	0.20	max 5 % in sieve 0.2 mm · pass-through 0.09 mm

Classification proper to the Chronital line, according to manufacturer nomenclature. Unlike carbon steel shot, stainless shot does not follow SAE J-444: the approximate size equivalence is S300 (Chronital) ≈ S660 (SAE) and S10 (Chronital) ≈ S70 (SAE), although composition and operating behavior differ. The “Specification” column indicates the two limits of the granulometric band: maximum on the next coarser sieve (coarse side) and minimum pass through the nominal sieve. Sieves in metric system — ISO 565 and US mesh equivalence available on request. For the full sieve matrix, download the technical datasheet in PDF.

Hardness

The hardness of stainless spherical shot is not controlled by prior tempering as in carbon steel shot; instead, it increases progressively during blasting by cold work (work hardening) induced by continuous impact. The shot starts in a relatively soft supply state and, once in the operating cycle, evolves to its regime hardness. This transformation is irreversible and delivers a stable operating mix with uniform hardness throughout the media life:

Estado	Vickers (HV)	Rockwell C (HRC)	Behavior
Supply (virgin shot)	275	~28	Austenitic structure with delta ferrite < 10 %
Operating mix (regime)	475	~47	Martensite induced by cold deformation

Measurements taken with the Vickers method (HV) under loads of 0.5 to 1 kgf, in line with industrial practice for spherical grains. Conversion to Rockwell C (HRC) follows standard ASTM E140 tables. Regime hardness is reached within the first hours of operation and remains stable throughout media life. Unlike carbon steel shot, stainless shot is not offered in different hardness grades (H, P, PE): the entire Chronital line evolves through work hardening to the same operating level. Media density is approximately 4.5 g/cm³, lower than carbon steel (~7.4 g/cm³), reducing impact energy on the part and allowing operation on delicate substrates without deformation.

SHOT SELECTION BY APPLICATION

Which application do you need to perform?

Select the application to see the recommended Chronital grade.

The table shows the most commonly used Chronital grade for each application, according to industrial practice. It is not a prescriptive rule: most applications accept more than one valid grade, and the choice between Chronital and Chronital 13 depends on the level of corrosion resistance required. The final selection depends on the available equipment, the part to be treated, the targeted productivity and the required finish. Consult our technical team for a specific recommendation.

Application	S10–S30	S40–S60	S100–S150	S200–S300	Chronital	Chronital 13
Aluminium casting and forging		✓	✓	✓	✓
Zinc and zamak die-casting	✓	✓			✓
Blasting of aluminium profiles prior to anodizing	✓				✓
Mold cleaning (glass, extrusion, injection)	✓				✓
Stainless steel boilermaking	✓	✓	✓		✓	✓
Removal of weld discoloration on stainless parts	✓	✓				✓
Decorative bright finish on stainless parts	✓	✓				✓
Blasting of granite and prestressed concrete	✓	✓	✓	✓	✓
Sand removal and foundry cleaning of non-ferrous metals			✓	✓	✓
Critical applications with high corrosion resistance						✓

RESOURCES AND RELATED LINKS

Technical data sheet, alternative abrasives and technical reports

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