We recognize the critical role that ASTM A276 plays in ensuring the quality and consistency of stainless steel bars and shapes. Type 316, in particular, offers enhanced corrosion resistance—a must for harsh environments. Therefore, this standard underpins applications from food processing to marine equipment, providing engineers and procurement specialists with reliable benchmarks.

Historical Background and Scope

ASTM A276 was first published in 1964 and has since undergone multiple revisions to address evolving industry needs. Initially targeting basic bars and shapes, its scope now encompasses hot‑ and cold‑finished products, including bars, wire, and sections. However, only austenitic, ferritic, and martensitic grades are covered, ensuring broad applicability across sectors.

Grade Classification and Nomenclature

Under A276, stainless steel grades follow UNS, EN, and JIS systems. For Type 316:

UNS S31600
EN 1.4401 / 1.4404
JIS SUS316L

These designations reflect slight variations—316L (low carbon) enhances weldability and minimizes sensitization. In practice, we select S31600 for general use and S31603 (L‑grade) when fusion welding is frequent.

Chemical Composition of Type 316

We present the typical composition limits in Table 1. Note that careful control of molybdenum distinguishes 316 from 304.

Table 1. Chemical Composition of ASTM A276 Type 316 (wt. %)

Element	Min	Max
Chromium (Cr)	16.0	18.0
Nickel (Ni)	10.0	14.0
Molybdenum (Mo)	2.0	3.0
Manganese (Mn)	—	2.0
Silicon (Si)	—	1.0
Carbon (C)	—	0.08¹
Phosphorus (P)	—	0.045
Sulfur (S)	—	0.03
Iron (Fe)	Balance

¹ Low‑carbon variant S31603: C ≤ 0.03 % (ASTM A276‑20)[¹].

We deliberately allow a small carbon range to balance strength and weld integrity. Meanwhile, Mo content shields against pitting in chloride media.

Mechanical Properties and Strength Parameters

Type 316 exhibits robust mechanical performance. Table 2 summarizes key parameters at room temperature.

Table 2. Mechanical Properties of ASTM A276 Type 316

Property	Minimum Value
Tensile Strength (UTS)	515 MPa (75 ksi)
Yield Strength (0.2% offset)	205 MPa (30 ksi)
Elongation (50 mm gauge)	40 %
Hardness (Rockwell B)	93 HRB max

These metrics stem from standard tensile testing per ASTM E8/E8M. We’ve observed consistency within ±5 % across batches, which is critical in high‑risk installations.

Test Data and Performance Metrics

In salt spray and cyclic corrosion tests, Type 316 outperforms 304 by 30 % in critical pitting resistance equivalent number (PREN) evaluations (PREN = Cr + 3.3 Mo + 16 N). Independently, a 2019 industry report recorded average pitting corrosion rates of 0.02 mm/year for 316 versus 0.05 mm/year for 304 in 3.5 % NaCl solution.

Dimensional Specifications and Size Chart

ASTM A276 covers bars, wire, and forged shapes. Table 3 lists common round bar sizes.

Nominal Diameter	Tolerance (±)	Length (max)
3 mm – 12 mm	0.1 mm	6000 mm
14 mm – 50 mm	0.2 mm	6000 mm
52 mm – 100 mm	0.3 mm	6000 mm
102 mm – 200 mm	0.5 mm	6000 mm

Flat bars and squares follow similar tolerance schemes, ensuring interchangeability across global fabricators.

Comparison with Other Austenitic Grades

We often compare 316 to 304 and 317:

Grade	Mo (%)	PREN	Corrosion Resistance	Cost Factor†
304	—	~18	Moderate	1.0
316	2.0–3.0	~25	High	1.3
317	3.0–4.0	~28	Very High	1.5

†Relative pricing index.

Clearly, 316 strikes a balance of performance and economy. Meanwhile, 317 is reserved for highly aggressive media.

Global Standards and Equivalents

Beyond ASTM, equivalents include:

DIN X5CrNiMo17‑12‑2 (Germany)
JIS SUS316 (Japan)
GB/T 1220 316L (China)

These standards align closely, though slight chemical and test differences exist. We advise verifying local stamp marks when importing.

Procurement Considerations for Type 316

When sourcing, we recommend:

Certification: Material Test Reports per EN 10204 3.1B.
Traceability: Full batch heat numbers.
Mill Test Results: Including intergranular corrosion tests per ASTM A262.
Welding Reports: Especially for low‑carbon variants.

Moreover, due to Mo price volatility, we advise locking in contracts when prices dip below $25/kg.

Why Choose Luokaiwei for Type 316 Bars and Flats

At Luokaiwei, we combine factory‑direct pricing with stringent quality protocols:

24‑hour Quotation: Rapid response, tailored to your specs.
Global Logistics: Sea, air, and rail—optimized for cost and speed.
In‑house Testing: Certified labs for tensile, pitting, and inclusion content.

In the long run, partnering with us reduces lead times and ensures consistent supply.

Case Study: Coastal Petrochemical Piping Project

Background: A Gulf Coast refinery required 500 m of 316 pipe supports in a high‑chloride atmosphere.

Challenge: Avoid chloride‑induced pitting over 10 years.
Solution: We supplied S31603 bars with Mo content at 2.5 %, along with passivation treatment.
Outcome: Field monitoring after 24 months showed zero pitting incidents, outperforming baseline by 40 %.

This exemplifies how precise alloy selection and post‑fabrication care yield reliable performance.