304 304L Dual Certified Stainless Steel pipe

What Is 304 / 304L Dual Certified Stainless Steel Pipe?

304 / 304L dual certified stainless steel pipe refers to pipes that meet the chemical composition and mechanical property requirements of both ASTM A312 TP304 and TP304L. These pipes offer the corrosion resistance and strength of 304 stainless steel, combined with the low carbon content of 304L, which enhances weldability and reduces the risk of intergranular corrosion.

 

Firstly, let us see 304 and 304L conforming to ASTM A312 specification for welded and seamless tubing, and comparing in difference, usually, we consider 304L to be low carbon 304, and variation from 304, "L" means low content in carbon element.

Specification

Property	304 Stainless Steel	304L Stainless Steel
Standard	ASTM A312 / A213 / A269	ASTM A312 / A213 / A269
UNS Number	S30400	S30403

 

we can see that there are two differences in composition, Carbon and Nickel content, Nickel content ranges from 8 to 12% for 304L, and 304 Nickel content ranges from 8 to 11%, it is not so that important, carbon content of 304 / 304L dual certification must not exceed 0.035%.

Grade	C	Si	Mn	Cr	Ni	Mo	S	P
304	0,08	1,0	2	18 – 20	8 – 11	–	0,03	0,045
304L	0,035	1,0	2	18 – 20	8 – 12	–	0,03	0,045

Secondly, let us check 304 and 304L stainless steel mechanical properties in minimum value.

Grade	Tensile Strength(Mpa)	Yield Point(Mpa)	Elongation(%)
TP304	515	205	35
TP304L	485	170	35

 

 

What does "dual certified" mean in stainless steel pipe?

"Dual certified" means the pipe complies with both 304 and 304L standards. It contains a low carbon content (≤0.03%) suitable for welding (304L), while also meeting the mechanical strength of 304. This is particularly valuable in construction, pressure piping, and food equipment industries, where both strength and corrosion resistance are required.

 

What are the advantages of using 304/304L dual certified pipe?

Weldability: 304L's low carbon minimizes carbide precipitation.

Corrosion Resistance: Ideal for food-grade, chemical, and atmospheric exposure.

Inventory Efficiency: Engineers can standardize a single material for projects requiring either grade.

Regulatory Compliance: Meets both ASME and ASTM standards for pressure applications.

 

Is dual certified 304/304L stainless steel pipe suitable for welding?
Yes. One of the main reasons for dual certification is to provide enhanced weldability. The low carbon in 304L minimizes sensitization (carbide precipitation at grain boundaries), which could otherwise lead to intergranular corrosion after welding. Dual certified pipe is widely used in welded applications without the need for post-weld heat treatment.

 

What standards cover 304/304L stainless steel pipes?
Dual certified pipes typically comply with the following standards:

ASTM A312 – Seamless and welded austenitic stainless steel pipes for high temperature and general corrosive service

ASTM A213 / A269 – For seamless and welded tubing used in heat exchangers or condensers

ASME B36.19M – Covers stainless steel pipe dimensions

Certifications can also include PED, AD2000, EN10216-5, and ISO 9001, depending on customer requirements.

 

If you're looking for a versatile, cost-effective, and reliable stainless steel solution, 304 / 304L dual certified pipe is ideal for both general-purpose and high-performance applications. Whether you're a buyer for construction, food processing, or petrochemical projects, this material offers excellent corrosion resistance, weldability, and global compliance.Contact us today for a free quote or technical consultation.Email: info@gneestainless.com