• May 25th 2023

Steel is an essential material in various industries, including construction, automotive, and manufacturing. It comes in various grades, each with its unique properties and applications. In this essay, we will compare two popular steel grades, 12L14 and 1018, to determine their characteristics, advantages, disadvantages, and suitable applications. The essay is organized into the following sections:

  • Introduction
  • Composition
  • Mechanical Properties
  • Machinability
  • Weldability
  • Applications
  • Summary

Introduction

12L14 and 1018 are both variants of carbon steel. Carbon steels are alloys of iron and carbon, with small amounts of other elements such as manganese, silicon, and sulfur. These steels are categorized based on their carbon content. 12L14 and 1018 are considered low-carbon steels, with carbon content less than 0.3%.

Composition

12L14 Steel

12L14 steel is a free-machining, resulfurized, and rephosphorized carbon steel. Its composition includes:

  • Carbon (C): 0.15%
  • Manganese (Mn): 0.85-1.15%
  • Phosphorus (P): 0.04-0.09%
  • Sulfur (S): 0.26-0.35%
  • Lead (Pb): 0.15-0.35%

The addition of lead, sulfur, and phosphorus improves the machinability of 12L14 steel. These elements form inclusions in the steel, which act as chip breakers during machining, reducing friction and improving surface finish.

1018 Steel

1018 steel is a mild, low-carbon steel with good weldability and machinability. Its composition includes:

  • Carbon (C): 0.15-0.20%
  • Manganese (Mn): 0.60-0.90%
  • Phosphorus (P): 0.04% max
  • Sulfur (S): 0.05% max

The composition of 1018 steel is simpler than that of 12L14 steel and does not contain any lead, which makes it more environmentally friendly. AISI 1018 Steel Equivalent Material

https://www.youtube.com/watch?v=Nqn9gwah-FM

Mechanical Properties

12L14 Steel

The mechanical properties of 12L14 steel include:

  • Tensile Strength: 78,000 psi (538 MPa)
  • Yield Strength: 60,000 psi (414 MPa)
  • Elongation: 10%
  • Hardness: B 84

These properties make 12L14 steel suitable for applications that require good machinability but do not demand high strength or ductility.

1018 Steel

The mechanical properties of 1018 steel include:

  • Tensile Strength: 63,800 psi (440 MPa)
  • Yield Strength: 53,700 psi (370 MPa)
  • Elongation: 15%
  • Hardness: B 71

Compared to 12L14 steel, 1018 steel has lower tensile and yield strength but higher elongation and ductility. This makes it more suitable for applications that require moderate strength and good formability.

Machinability

12L14 Steel

12L14 steel is well-known for its excellent machinability. The addition of lead, sulfur, and phosphorus increases its cutting speed and reduces tool wear. As a result, 12L14 steel is often used in high-volume production environments where high-speed machining is required.

1018 Steel

1018 steel also has good machinability, but it is not as high as that of 12L14 steel. The absence of lead and the lower sulfur content in 1018 steel result in a slower cutting speed and increased tool wear compared to 12L14 steel. However, 1018 steel is still considered easy to machine, making it suitable for general-purpose applications.

Weldability

12L14 Steel

Due to its high sulfur and lead content, 12L14 steel has poor weldability. The inclusions formed by these elements can cause porosity, cracks, and poor fusion during welding, which can compromise the strength and integrity of the welded joint. As a result, 12L14 steel is not recommended for applications that require welding.

1018 Steel

In contrast, 1018 steel has excellent weldability due to its low carbon content and simple composition. It can be easily welded using various welding processes, such as shielded metal arc welding (SMAW), gas metal arc welding (GMAW), and gas tungsten arc welding (GTAW). This makes 1018 steel a preferred choice for applications that require welding.

Applications

12L14 Steel

Given its excellent machinability and low strength, 12L14 steel is primarily used in applications that require high-speed machiningand good surface finish, such as:

  • Bushings
  • Couplings
  • Fittings
  • Nuts and bolts
  • Shafts
  • Spacers
  • Studs

1018 Steel

Due to its good weldability, machinability, and formability, 1018 steel is suitable for a wide range of applications, including:

  • Automotive components
  • Base plates
  • Brackets
  • Fixtures
  • Gears
  • Machinery parts
  • Structural components

Summary

12L14 and 1018 are both low-carbon steels, but they differ in terms of composition, mechanical properties, machinability, weldability, and applications.

12L14 steel is a free-machining steel with excellent machinability due to its high sulfur, phosphorus, and lead content. However, these elements also make it unsuitable for welding. It has lower tensile and yield strength compared to 1018 steel, making it suitable for high-speed machining applications that do not require high strength.

On the other hand, 1018 steel has good machinability, excellent weldability, and higher ductility than 12L14 steel. It is suitable for a wide range of applications that require moderate strength, good formability, and welding. Additionally, its simpler composition and lack of lead make it more environmentally friendly.

In conclusion, 12L14 steel is the preferred choice for high-volume production environments that require high-speed machining and good surface finish, while 1018 steel is more versatile and suitable for applications that require welding and moderate strength. When selecting between these two steel grades, it is essential to consider the specific requirements of the intended application, such as strength, machinability, weldability, and environmental impact.