Carbon & Low Alloy Steel

Carbon & Low Alloy Steel Investment Casting Materials

Carbon and Low alloy steel castings are ideal for general engineering purposes. They can be used in a wide variety of low and medium strength applications and provide useful general properties at a relatively low cost.

For more information please see table BS3146 (1974), Part 1.

BS 3146: (1974) PART 1: CLA1

Description
Carbon Steel Alloy Castings are ideal for general engineering purposes. The three grades of materials can be used in a wide variety of low and medium strength applications where reasonable ductility is useful but good hardenability not required. Considerable improvements in mechanical properties can be achieved by heat treatment. These alloys provide useful general properties at a relatively low cost.

Additional Information

• Weldability is characteristic of plain carbon steels, the low carbon grade being straightforward while the other two grades will normally require preheating and stress relieving. Conventional gas or electric welding methods with the use of fluxes will generally be satisfactory (reference should be made to BS3146 (1974), Part 1, Appendix A).
• Machinability is variable depending primarily on composition and heat treatment. For very low carbon alloys surface finish is generally poor and high speeds, constant tool pressures and high speed tools should be used. As the carbon content increases machinability can become excellent, especially for medium range carbon content alloys in the normalised condition and relatively high carbon content alloys in the hardened and tempered condition.

BS 3146: (1974) PART 1: CLA2

Description
1½% manganese pearlitic steel castings for general engineering purposes. This alloy has improved properties over plain carbon steels of similar strength, particularly with regard to proof stress, ductility and toughness, while at the same time being readily weldable and machinable. This combination of properties makes the alloy suitable for applications where many of the characteristics of a low alloy steel are required but the high cost is not justified.

Additional Information

• Weldability – satisfactory providing reasonable precautions are taken. Welding should not be carried out in the as cast condition and severe quenching in the welding area should be avoided. Gas or electric arc methods with fluxes are suitable, although gas methods are often preferred as the gas flame can be used for pre- and post-weld heating. Inert gas shielded arc methods are not justified and can result in excessive localised heating. Post welding treatment must be carried out and should consist of at least stress relieving or local tempering but preferably complete re-hardening and tempering (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA3

Description
700 – 850 N/m m ² alloy steel castings for structural and general engineering purposes. Unless specified by the purchaser the choice of the alloy is left to the discretion of the founder. The two materials are typical of compositions chosen for this specification. These steels combine medium strength with excellent overall mechanical properties. The specification dictates that neither sulphur nor phosphorus shall exceed 0.035%.

Additional Information

• Weldability satisfactory providing reasonable precautions are taken. Welding should not be carried out in the as-cast condition and severe quenching in the weld area should be avoided. Gas or electric arc methods with fluxes are suitable, although gas methods are often preferred as the gas flame can be used for pre- and post-weld heating. Inert gas shielded arc methods are not justified and can result in excessive localized heating. Post welding treatment must be carried out and should consist of at least stress relieving or local tempering, but preferably complete re-hardening and tempering (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good

BS 3146: (1974) PART 1: CLA4

Description
850 – 1000 N/mm ² alloy steel castings for structural and general engineering purposes. Unless specified by the purchaser the choice of alloy is left to the discretion of the founder. The two materials are typical of compositions chosen for this specification. The steels combine medium strength with excellent overall mechanical properties. The specification dictates that neither sulphur nor phosphorus shall exceed 0.035%.

Additional Information

• Weldability satisfactory, providing reasonable precautions are taken. Welding should not be carried out in the as cast condition and severe quenching in the weld area should be avoided. Gas or electric arc methods with fluxes are suitable, although gas methods are often preferred as the gas flame can be used for pre- and post-weld heating. Inert gas shielded arc methods are not justified and can result in excessive localized heating. Post welding treatment must be carried out and should consist of at least stress relieving or local tempering, but preferably complete re-hardening and tempering (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA5

Description
A steel suitable for components with medium to high tensile requirement and good ductility and toughness. Unless specified by the purchaser the choice of alloy is left to the discretion of the founder. The material for which the chemical composition is quoted below is a typical composition chosen for this specification. The specification dictates that sulphur content shall not exceed 0.020% and phosphorus 0.025%.

Additional information

• Weldability is good but pre- and post-weld heating is required for post-treatment preferably hardening and tempering. These alloys are readily welded by metal arc, gas, flash and resistance methods (reference should be made to BS3146 (1974), Part 1, Appendix A)
• Machinability is good.

BS 3146: (1974) PART 1: CLA7

Description
Steel castings for general engineering purposes may be used at temperatures up to 400°C. Suitable for nitriding.

Additional Information

• Weldability is good but pre- and post-weld heating is required for post treatment preferably hardening and tempering. The alloy is readily weldable by metal arc, gas, flash and resistance reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA8

Description
Carbon Steel castings for surface hardening by a local heating and quenching process.

Additional Information

• Weldability is good but pre- and post-weld heating is required (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA9

Description
A low carbon case-hardening steel giving a surface hardness of 850-950, after carbonizing or cyaniding and heat treatment, combined with good wear and shock resistance.

Additional Information

• Weldability is good (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good in the normalized condition.

BS 3146: (1974) PART 1: CLA10

Description
3% Nickel case-hardening steel, suitable for carburizing or cyanide hardening. Medium tensile strength core with reasonable shock resistance. Typical applications are high duty parts subject to wear under reciprocating or intermittent loading – pawls, ratchets, levers and connecting rods.

Additional Information

• Weldability is good (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA11

Description
A 3% Cr-Mo steel which can be hardened up to 900 – 1050 VPN, by nitriding and with the minimum of distortion. Medium to high tensile strength in the core with good ductility and shock resistance. Suitable for moving parts requiring resistance to abrasion or wear, e.g. crank, pins, crank shafts and similar parts.

Additional Information

• Weldability is good but pre- and post-weld heating is required for post treatment preferably hardening and tempering (reference should be made to BS 3146 (1974), Part 1, Appendix A).
• Machinability is good.

BS 3146: (1974) PART 1: CLA12

Description
Medium carbon 1% chromium steels giving a high through hardness and an abrasive-resistant structure on quenching. The castings are usually tempered to develop properties related to specific applications where maximum hardness would be undesirable. Used for parts where medium or high stresses are applied also heavy duty applications in contact with abrasive materials.

Additional Information

• Weldability is reasonable pre- and post-weld heating being important (reference should be made to BS3146 (1974), Part 1, Appendix A).
• Machinability is satisfactory in the annealed condition.

BS 3146: (1974) PART 1: CLA13

Description
Nickel-Molybdenum, low alloy steel for carburizing or cyanide hardening. Medium strength core with reasonable shock resistance. Typical applications are high duty parts subject to wear under reciprocating or intermittent loading. Can be used as an alternative to CLA10.

Additional Information

• Weldability – readily welded
• Machinability – readily machinable.