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Magnetic particle testing (MPT) is a non-destructive testing (NDT) method used to detect surface and near-surface defects in ferromagnetic materials. It involves magnetizing the component and applying magnetic particles that accumulate at discontinuities like cracks or voids, making them visible under UV light or contrast. However, the key question is whether MPT can be effectively used on Type 304 stainless steel, a popular austenitic alloy. Type 304, often referred to as SA-240 304 material or AISI 304, is widely utilized in industries due to its excellent corrosion resistance and formability. To answer this, we need to examine the material's properties.
Type 304 stainless steel is austenitic, which means it has a face-centered cubic crystal structure that renders it SS 304 non magnetic in its standard annealed condition. This is a critical factor because MPT relies on the material being ferromagnetic to create a magnetic field and attract particles to defects.
The SS 304 plate density is approximately 7.93 g/cm³, but density isn't the issue—it's the magnetic permeability. Austenitic steels like Type 304 have low magnetic permeability (close to 1), unlike ferritic or martensitic steels (e.g., 430 grade), which are magnetic and suitable for MPT.
In practice, attempting MPT on Type 304 would yield poor results, as the material doesn't support sufficient magnetization. For instance, in SA-240-304 material used for pressure vessels, inspectors often turn to alternative NDT methods to avoid false negatives.
The primary reason MPT can't be used on Type 304 is its austenitic microstructure. During manufacturing, such as in sa 240 type 304 304l variants, the alloy is stabilized with nickel, preventing transformation to magnetic phases. Even in cold-worked conditions, where some magnetism might develop due to strain-induced martensite, it's inconsistent and unreliable for MPT. For materials like sa 240 304l material, which is low-carbon for better weldability, the non-magnetic property remains dominant.
Gangsteel, a top manufacturer in China, confirms that for sa 240 304 material plates, MPT is not recommended. Instead, alternatives like dye penetrant testing (PT) or ultrasonic testing (UT) are preferred for detecting surface cracks in sa 240 gr 304 plate.
Since MPT is ineffective, several alternatives are used for Type 304:
These methods ensure reliable inspection for sa 240 gr 304/304l components.
Type 304's ss 304 plate density of 7.93 g/cm³ makes it lightweight yet strong. Its mechanical properties include a tensile strength of 515 MPa min and yield strength of 205 MPa. Applications include sa 240 304 density calculations for chemical tanks, plate 2 mm sus 304 for thin linings, and plat stainless 304 for architectural panels. In high-heat scenarios, sa 240 304h material is preferred.
Gangsteel supplies asme sa 240 ss304 and sa240 grade 304 with certifications.
SA-240 304 has higher carbon for strength, while SA-240 304L's low carbon improves weldability and corrosion resistance.
Yes, what is sa 240 304 is FDA-compliant for food equipment due to its hygiene and resistance.
Ss sheet 304 priceand ss 304 plate price range from $1,820 to $3,584 per MT, depending on region.
For mild marine, yes; for harsh, use sa240 304 stainless with molybdenum grades like 316.
What is SA240is the ASME standard for stainless steel like sa240 tp 304.
ASTM A516 GR 70 equivalent materials is such as ASME SA516 GR 70, EN 10028 P355GH, and BS1501 224-490 A & B, sh
we supply high-quality A516 Gr 70 steel plate for pressure vessel applications and other standards like ASTM A2
EN10028-2 P355GH for High-Strength Low-Alloy Columbium-Vanadium Structural Steel EN10025-2 S355J2 Structural St
We export A240 304L Stainless Coil 2B, NO.1 No.4 surface, the thickness 0.1mm to 3mm, 3mm to 22mm, Mother mill
