What Is Salt Spray — ASTM B117?
The salt fog test is an experiment in which corrosion resistance is evaluated in an accelerated manner by exposing the sample to salt solution fog in a controlled cabin. It provides comparative data in a short time on corrosion behavior over many years in the natural atmosphere.
Purpose of Salt Spray — ASTM B117
The aim is to determine how long a coating or material provides protection in a corrosive environment and to compare different coating systems under the same conditions. The test does not give an absolute lifespan estimate; Used for quality control and specification compliance.
Which Products Is Salt Spray — ASTM B117 Applied To?
- Painted and coated metal parts
- Galvanised and zinc coatings
- Automotive body and fasteners
- White goods sheet metal components
- Hardware and fasteners used outdoors
In Which Sectors Is Salt Spray — ASTM B117 Used?
Standards Related to Salt Spray — ASTM B117
- ASTM B117tuz sisi (salt spray) korozyon testi test
Salt Spray — ASTM B117 Conditions
- Solution
- 5% NaCl (by mass), pH 6.5–7.2 for ASTM B117
- cabin temperature
- 35 °C ± 2 °C (neutral salt fog)
- Sis toplama debisi
- 80 cm² alanda 1,0–2,0 mL/saat
- sample angle
- 15°–30° from vertical
Equipment for Salt Spray — ASTM B117
- Salt fog chamber
- Atomizer and compressed air conditioning
- pH and conductivity meter
- Fog collection funnels
Sample Requirements for Salt Spray — ASTM B117
- At least three samples are recommended
- The sample surface must be clean and dry before testing.
- Cut edges must be properly masked
- Dimensions must comply with the cabinet shelf layout
Duration of Salt Spray — ASTM B117
According to the specification, it is applied in stages such as 24, 48, 96, 240, 480, 720 or 1000 hours. The duration is determined by the customer specification or product standard.
Salt Spray — ASTM B117 Procedure
- 1Samples are cleaned, marked and edges masked if necessary.
- 2Chamber conditions (temperature, solution, flow rate) are verified.
- 3Samples are placed on the rack at the defined angle.
- 4Continuous fog is applied for the specified period of time; Observations are recorded at intermediate control points.
- 5At the end of the exposure, samples are washed, dried and evaluated.
Salt Spray — ASTM B117 Acceptance Criteria
Acceptance criteria are defined in the product standard or customer specification, not in the test itself. Common criteria: no red rust after a certain period of time, no corrosion spread beyond the specified millimeter around the scratch.
Evaluation of Results
Evaluation is made by visual inspection and grading of defects such as blistering, rust, and scratch propagation. The results are comparative; Results obtained in different cabins cannot be matched exactly.
Salt Spray — ASTM B117 Report
- Applied standard and revision year
- Chamber conditions and verification records
- Exposure time and interim control observations
- Sample description and photographs
- Assessment result
Accreditation
EUROLAB holds internationally recognised accreditation obtained from accreditation bodies party to the IAF and ILAC multilateral recognition arrangements, under ISO/IEC 17025 for laboratory testing, ISO/IEC 17020 for inspection and surveillance, and ISO/IEC 17021-1 and ISO/IEC 17065 for system and product certification. This chain ensures the reports and certificates issued are accepted worldwide.
Whether this test can be offered within accredited scope depends on your product and the standard applied; since accreditation is method-based, the scope is confirmed in writing at the quotation stage.
Scope and authorisationsRelated Regulations
- Product based specifications
- Automotive OEM standards (VDA, SAE)
Metal and Metallurgy Testing — What Does This Testing Field Cover?
The section below describes the field that the Salt Spray test belongs to; the conditions and acceptance criteria of this particular test are given in the sections above. The scope specific to your product is confirmed in writing at the quotation stage.
Metal and metallurgical testing determines the load a metal or a welded joint can carry, how it fails and what its internal structure looks like. The output of this family is often not about the product itself but about the identity of the MATERIAL: is the steel really of the declared grade, does the weld seam deliver the strength the design assumes, does the casting contain an unacceptable internal defect?
The practical importance of the field comes from the fact that a metal part rarely fails gradually. A plastic part deforms, ages, cracks and usually gives warning. A weld seam or a fastener, by contrast, often breaks without warning — especially where fatigue and brittle fracture are involved. That is why in fields such as pressure equipment, lifting gear, structural steel and pipelines, material testing is a requirement of REGULATION rather than of design.
The family brings together three groups of methods, and each answers a different question. Mechanical tests quantify how the material behaves under load. Non-destructive examination looks for defects without damaging the part. Metallography and chemical analysis explain why the material behaves the way it does — through grain structure, phase distribution, inclusion content and alloy composition.
The acceptance criterion for these tests almost never comes from the test standard, and this is the key to understanding the field. The test standard says how the measurement is to be made; the acceptable values come from the product standard, the material grade or the fabrication code. ISO 6892-1 tells you how to run a tensile test; EN 10025 tells you what yield strength that steel must deliver. When reading a report, the product standard it was assessed against is essential.
Sampling is an inseparable part of the result in this field. Two specimens taken from the same heat may give different values depending on the direction and location they were taken from; in rolled products, specimens parallel and perpendicular to the rolling direction produce different results. Product standards therefore also govern sampling location and orientation, and the report must document this.
Method groups in this field
Mechanical tests
Tensile, compression, bending, notch impact (Charpy), hardness (Brinell, Vickers, Rockwell), fatigue, creep and fracture toughness. These give the behaviour of the material under load in numerical form.
Non-destructive examination
Radiography, ultrasonic examination, penetrant, magnetic particle and visual examination. It looks for surface and internal defects without damaging the part and is an indispensable step in welded fabrication.
Metallography
Specimen preparation, etching and microscopic examination. Grain size, phase distribution, inclusion content, case depth and the weld heat-affected zone are assessed.
Chemical analysis
Alloy composition is verified by optical emission spectrometry and wet chemistry; confirmation of the material grade runs through this step.
Corrosion behaviour
Salt spray, pitting and crevice corrosion and intergranular corrosion tests. In stainless steels these can indicate the quality of the heat treatment.
Commonly confused in this field
- A material certificate (such as EN 10204 3.1) is not a test report; it is the manufacturer's declaration. In critical applications independent verification is carried out, and the two must not be confused.
- ASTM and ISO tensile tests measure the same quantities but use different specimen geometries; the results are not treated as directly equivalent, and whichever the specification calls for is the one applied.
- Conversion tables between hardness and strength are APPROXIMATE. Calculating yield strength from hardness is not sufficient evidence for material acceptance.
- In non-destructive examination, "no defect found" does not mean there is no defect; defects below the detection limit of the method may be present. The report must state the method applied and the sensitivity level.
- A weld seam passing does not show that the welder or the procedure is qualified; these are separate processes.
Which decisions these results support
- Verifying the material certificate and accepting incoming material
- Approving welded fabrication; welder and procedure qualification
- Manufacturing control of pressure equipment and structural components
- Failure analysis and determining the root cause of field damage
- Verifying heat treatment and surface treatment processes
Related Tests
Frequently Asked Questions About Salt Spray — ASTM B117
What is the difference between ASTM B117 and ISO 9227?
They both describe a neutral salt fog experiment, and the conditions largely overlap. Differences are in solution preparation, pH range, sample placement, and reporting details. Which standard will be applied is determined by the product specification.
Does the salt mist test give the real lifespan of the product?
It doesn't. The test is an accelerated comparative experiment; There is no direct conversion factor with field life. For real environmental behavior, cyclic corrosion tests give more representative results.
How many samples should I send?
Generally, at least three samples are recommended. The exact quantity depends on the standard to be applied and the evaluation method in your specification; It is notified in writing at the offer stage.