Chemical Composition Element Specified / Typical Range (wt. %) C ≤0.08 Mn ≤2.00 Si ≤1.00 P ≤0.045 S ≤0.030 Cr 17.0–20.0 Ni 9.0–13.0 Mo — N ≤0.10 Nb+Ta ≥10×C; ≤1.00 Fe Balance

Mechanical Properties Property Minimum / Requirement Tensile Strength, min. 515 MPa Yield Strength, 0.2%, min. 205 MPa Elongation, min. 30% Hardness As required by the applicable fitting specification

Pump and equipment connections Process piping size transitions Chemical and petrochemical plants Oil and gas and energy systems Water treatment and desalination Food, pharmaceutical and general industrial piping

Chemical Composition Element Specified / Typical Range (wt. %) C ≤0.08 Mn ≤2.00 Si ≤1.00 P ≤0.045 S ≤0.030 Cr 17.0–20.0 Ni 9.0–13.0 Mo — N ≤0.10 Nb+Ta ≥10×C; ≤1.00 Fe Balance

Mechanical Properties Property Minimum / Requirement Tensile Strength, min. 515 MPa Yield Strength, 0.2%, min. 205 MPa Elongation, min. 30% Hardness As required by the applicable fitting specification

Pump and equipment connections Process piping size transitions Chemical and petrochemical plants Oil and gas and energy systems Water treatment and desalination Food, pharmaceutical and general industrial piping

347 Stainless Steel Reducers

Grade: 347/347H

Types:

Concentric Reducer, Eccentric Reducer, Straight Reducer, Seamless Reducer, Welded Reducer

Standard:

ASME B16.9, EN 10253-4:2025, JIS B2312/2313

347 is a niobium-stabilized austenitic stainless steel developed for improved resistance to intergranular corrosion after welding and during elevated-temperature service. It has a chemistry broadly related to 304, with niobium added for stabilization. 347 fittings are commonly used in refinery, petrochemical, thermal and chemical-process piping where welded joints experience elevated temperatures or repeated thermal cycles.

Chemical Composition

Element	Specified / Typical Range (wt. %)
C	≤0.08
Mn	≤2.00
Si	≤1.00
P	≤0.045
S	≤0.030
Cr	17.0–20.0
Ni	9.0–13.0
Mo	—
N	≤0.10
Nb+Ta	≥10×C; ≤1.00
Fe	Balance

Mechanical Properties

Property	Minimum / Requirement
Tensile Strength, min.	515 MPa
Yield Strength, 0.2%, min.	205 MPa
Elongation, min.	30%
Hardness	As required by the applicable fitting specification

Pump and equipment connections
Process piping size transitions
Chemical and petrochemical plants
Oil and gas and energy systems
Water treatment and desalination
Food, pharmaceutical and general industrial piping

Introduction

Specification

Chemical Composition

Element	Specified / Typical Range (wt. %)
C	≤0.08
Mn	≤2.00
Si	≤1.00
P	≤0.045
S	≤0.030
Cr	17.0–20.0
Ni	9.0–13.0
Mo	—
N	≤0.10
Nb+Ta	≥10×C; ≤1.00
Fe	Balance

Mechanical

Mechanical Properties

Property	Minimum / Requirement
Tensile Strength, min.	515 MPa
Yield Strength, 0.2%, min.	205 MPa
Elongation, min.	30%
Hardness	As required by the applicable fitting specification