Necked Welding Flange 16Mn Introduction

The necked flat welding flange with material classification 16Mn is categorized by material. The English abbreviation for necked flat welding flange is: SO.

16Mn flange is a low-alloy high-strength structural steel: containing 0.1%-0.25% carbon, with the main alloying elements including manganese (Mn), silicon (Si), vanadium (V), niobium (Nb), and titanium (Ti).

16Mn is an old Chinese standard grade, now categorized as low-alloy high-strength structural steel, with the current grade being Q345. However, Q345 steel replaces not only the 16Mn steel but also multiple grades such as 12MnV, 14MnNb, 18Nb, 16MnRE, and others from the old grades.

So, the features of the 16Mn socket welding flange with neck are:

The neck-flanged焊接flange made of 16Mn steel is a carbon-manganese steel with a carbon content of approximately 0.16% and a yield point of 343MPa (falling within the 343MPa strength grade). 16Mn steel has a low alloy content and excellent weldability, typically requiring no pre-weld heat treatment. However, due to its slightly higher tendency for quenching hardening compared to low-carbon steel, preheating measures are necessary when welding in low temperatures (such as outdoor work during winter) or on structures with high rigidity and thickness to prevent cold cracks.

Specification Model

DN15-DN1000

Pressure Rating

PN6-PN100

Sealing Surface Type

Roughness (RF)

Full Flat (FF)

Concavo-convex (MFM)

Concave (FM)

Convex (M)

Mortise and tenon surface (TG)

The concavo-convex flanged flat welding flange (MFM) is for matching use.

Compliance Standards

National Standards, Chemical Industry Department Standards, ANSI Standards, DIN Standards, JIS Standards, etc.

Connection Type

Same welding process as flat焊接 flange, single-sided welding, double-sided nut connection.

In simple terms, it involves inserting the pipe into the inside diameter of the neck welding flange and welding it in place, then securing both sides with bolts and nuts.

Production Process

Pure forging and semi-forging are suitable for necked butt-welding flanges (SO) and necked welding neck flanges (WN).

Oxygen furnace blanking, overall forging or finished forging cutting and shaping, high-precision CNC lathe turning, CNC radial arm drill boring.

Advantages and Disadvantages of 16Mn Socket Weld Flanges with Neck

Advantages: Necked butt-welding flanges are also a type of butt-welding flange due to their short neck, which enhances the flange's strength and improves its load-bearing capacity. Therefore, they can be used on piping systems with higher pressure.

Disadvantages: More expensive than flat welding flanges, and more prone to dings during transit due to its shape characteristics.

Procurement Recommendations

1: It's recommended to purchase from a reputable颈平焊法兰 manufacturer with a certain scale of production.

2: manufacturers of flanges need to provide material inspection reports and related documents for necked butt-welding flanges.

3: Necked flat weld flanges must have corresponding specification model stampings and markings.