AISI 304L Stainless Steel Sheet （UNS S30403，ASTM A240/A480）

Product Introduction

AISI 304L sheet (UNS S30403) is a low-carbon austenitic stainless steel sheet, offering superior weldability and enhanced resistance to intergranular corrosion. With a maximum 0.03% carbon content, these sheets are ideal for applications requiring extensive welding or exposure to corrosive environments.

If your operating environment consists of "atmosphere, fresh water, steam, alcohol, and weak organic acids" and requires a large amount of welding, 304L is the most economical and reliable choice. However, if the medium contains chloride ions (such as seawater or salt spray) or strong acids, please immediately consider 316L or a higher grade material.

A clear inquiry can avoid 99% of subsequent disputes.

1. Determine Material Standards and Grades:

Sheet Material Standards: ASTM A240/A480 (equivalent to GB/T 3280 in China). Unified Grades: UNS S30403 or AISI 304L.

2. Specifications and Conditions (Core! Condition determines everything):

Thickness, Width, Length (Tolerances refer to standards or special agreements).

Delivery Condition: Must be clearly stated!

No.1: Hot-rolled sheet, with an oxide scale on the surface. Used for subsequent processing or applications where surface finish requirements are not high.

2B: Most common condition. Cold-rolled, heat-treated, pickled, and passivated, with a matte silver-white surface. Used for most general applications.

BA: Bright annealed, mirror-like surface. Used for high-end decoration and appliance panels.

HL: Brushed sheet.

(Choose the appropriate surface based on your end use.)

3. Your Special Requirements:

Surface Quality: Clearly define acceptable standards for scratches, roller marks, color differences, etc.

Sheet Shape: Flatness is required; avoid warping or camber.

Packaging: Standard sheet metal packaging, wooden pallets, or do you require lamination and padding (to prevent scratches)?

Certificate of Quality: A Material Quality Certificate (MTR) conforming to standards is required for each batch.

The 304L market is rife with counterfeit and substandard products. Based on years of purchasing experience and lessons learned, we have established a simple and efficient three-step testing process.

1. Document Review (Basic):

Quality Assurance Certificate (MTR): Verify the steel mill name, furnace batch number, applicable standards, and measured values ​​of key elements Cr, Ni, and C.

2. Physical Inspection (Crucial, Mandatory):

Every time goods arrive at our office testing warehouse, we need to open the boxes and inspect the goods.

First, we conduct dimensional and visual inspections: Measure the thickness (paying special attention to whether there are negative tolerances) and check for serious surface defects.

Second, we conduct portable spectrometer testing (PMI - the killer tool): This is our most important on-site tool as a purchasing agent. We randomly select at least 3-5 plates from each batch and perform spectroscopic analysis at different locations on the plate surface. The core objective: Ensure Cr ≥ 18.0% and Ni ≥ 8.0%. Many counterfeit products on the market are 201 (low-nickel, high-manganese) or 304 (non-L) masquerading as genuine. PMI can instantly reveal these characteristics.

Magnetic Test (Auxiliary): Use a magnet to attract the material. 304L in its solution state should be essentially non-magnetic. If the magnetism is strong, it may be a 200 series or other material.

Additionally, customers can negotiate in advance to have the finished product sent for third-party testing (mandatory for new suppliers, but can be done periodically by long-term or existing suppliers): Take a small sample and send it to a third-party testing agency for a complete chemical composition analysis, comparing it with the quality assurance certificate.

(by weight, according to ASTM A240)

(Solution-annealed state)

• Chemical processing equipment
• Food & beverage industry machinery
• Architectural cladding & decorative trim
• Pharmaceutical storage tanks
• Automotive exhaust components

• Mill-certified materials with full traceability
• Competitive pricing for bulk orders
• Precision cutting (laser, waterjet, or shearing available)
• Global logistics support for timely delivery

Available in ASTM A240/ASME SA240 standards with additional certifications upon request. Contact us for technical specifications or custom requirements.

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