IS 318 LTB4 Brass Casting – Yellow Brass Grade 4

IS 318 LTB4 (Yellow Brass Grade 4) is the highest-zinc standard yellow brass casting grade in IS 318, equivalent to C85400 (USA) and CC752S (EN 1982). With approximately 59% copper and 37–39% zinc, IS 318 LTB4 has the lowest copper content of the IS 318 leaded brass grades, offering the most cost-effective option for decorative hardware, architectural fittings, and general commercial castings where moderate corrosion resistance and good machinability are sufficient.

Alloy Overview

IS 318 LTB4 (Cu 57–61%, Zn ~37–41%, Pb 1.3–2.5%) is at the alpha-beta boundary, providing good castability, adequate strength (260 MPa), and the highest machinability rating (85–90% CDA) of the IS 318 brass casting grades. The relatively low copper content makes LTB4 the most economical of the standard IS 318 brass casting grades, favoured for high-volume decorative and commercial hardware production where cost per kilogram is the primary selection criterion.

Material Composition – IS 318

Element	Min %	Max %	Typical %	Role
Copper (Cu)	57.0	61.0	59.0	Primary matrix, colour
Zinc (Zn)	Balance	Balance	~38.5	Strength, castability, colour
Lead (Pb)	1.3	2.5	1.8	Machinability
Tin (Sn)	–	0.50	0.10	Minor
Iron (Fe)	–	0.30	0.05	Impurity
Nickel (Ni)	–	0.50	–	Minor
Aluminium (Al)	–	0.50	–	Minor
Manganese (Mn)	–	0.20	–	Impurity
Antimony (Sb)	–	0.05	–	Impurity
Silicon (Si)	–	0.05	–	Impurity

Mechanical Properties

Property	Sand Cast	Die Cast	Standard
Tensile Strength (MPa)	260 min	295 min	IS 318
Yield Strength (MPa)	90	110	IS 1608
Elongation (%)	20%	23%	IS 1608
Hardness (HB)	60–85		IS 1756
Density (g/cm³)	8.47		–
Electrical Conductivity (%IACS)	24–26		–
Melting Range (°C)	875–930		–
Machinability (%)	85–90		CDA scale

International Equivalent Grades

Standard	Designation	Name
India (IS 318)	LTB4	Yellow Brass Grade 4
USA (ASTM B584)	C85400 / CDA 854	Yellow Brass Casting
Europe (EN 1982)	CC752S	CuZn37Pb2-C
Germany (DIN 1709)	CuZn37Pb2-C	Gelbguss
UK (BS 1400)	SCB1 (nearest)	Yellow Brass Casting
Japan (JIS H5111)	YBsC2	Yellow Brass Casting 2
ISO	CuZn37Pb2-C	Yellow Brass Casting
China (GB/T 1176)	ZCuZn40Pb2	铸造黄铜

Applications

IS 318 LTB4: decorative architectural hardware; furniture fittings; plumbing trim; high-volume pressure die castings; general commercial hardware and consumer product castings; cost-sensitive decorative components requiring good machinability and attractive finish.