Linotype metal is a hard lead alloy originally developed for hot-metal printing systems such as Linotype and Monotype machines. Unlike pure lead, linotype is a high-antimony, tin-bearing alloy engineered for hardness, dimensional stability, sharp edge retention, and superior castability.
It is one of the hardest commonly used lead alloys, designed to solidify with minimal shrinkage while preserving precise detail.
Typical Chemical Composition
| Element | Typical Content (%) |
|---|---|
| Lead (Pb) | 82 – 84 |
| Antimony (Sb) | 11 – 13 |
| Tin (Sn) | 3 – 5 |
| Copper (Cu) | ≤ 0.1 (trace) |
| Arsenic (As) | Trace |
Key Mechanical Properties
| Property | Typical Value |
|---|---|
| Tensile Strength | 60 – 80 MPa |
| Yield Strength | 35 – 45 MPa |
| Elongation | 1 – 3% |
| Hardness | 21 – 30 HB |
| Elastic Modulus | ~18 GPa |
| Impact Resistance | Low – Moderate |
Linotype hardness is approximately 5–7 times higher than pure lead.
Physical Properties
| Property | Value |
|---|---|
| Density | ~10.6 g/cm³ |
| Melting Range | 240 – 300 °C |
| Thermal Conductivity | ~25 W/m·K |
| Electrical Conductivity | Low |
| Solidification Shrinkage | Very Low |
| Machinability | Good |
Metallurgical & Strengthening Behavior
Linotype is a multiphase alloy consisting of a lead-rich matrix reinforced by antimony-tin intermetallic compounds. This fine eutectic structure is responsible for its exceptional hardness and dimensional stability.
| Strengthening Mechanism | Contribution |
|---|---|
| Intermetallic Hardening (Sb) | High |
| Solid Solution Strengthening | Moderate |
| Grain Refinement | Moderate |
| Cold Working | Limited |
| Heat Treatment | Not applicable |
Key Characteristics
✔ Very high hardness compared to lead
✔ Excellent casting fluidity
✔ Minimal shrinkage during solidification
✔ Sharp edge and fine detail retention
✔ Good wear resistance and dimensional stability
❌ Brittle compared to pure lead
❌ Poor ductility
❌ Lower corrosion resistance than pure lead
Refining & Processing Properties
Linotype alloy is produced by controlled melting of high-purity lead followed by precise addition of antimony and tin. Fluxing removes oxides before ingot or continuous casting.
| Process | Suitability |
|---|---|
| Casting | Excellent |
| Machining | Good |
| Extrusion | Poor |
| Rolling | Poor |
| Soldering | Good |
Applications of Linotype Alloy
Printing Industry (Traditional)
Letterpress type, Linotype and Monotype machines
Ballistics & Ammunition
Hard-cast bullets, slugs, precision projectiles
Industrial & Craft Applications
Jigs, fixtures, gauge blocks, pattern making, sculpture casting
Advantages
✔ Exceptional hardness and wear resistance
✔ High dimensional accuracy
✔ Excellent mold filling and cast detail
✔ Fully recyclable and reusable
Health, Safety & Handling
Linotype contains lead, antimony, and tin and must be handled with appropriate ventilation, PPE, and compliant waste management procedures.
Why Choose Linotype / Lead Alloy?
Choose linotype alloy when hardness, sharp detail retention, low-shrinkage casting, and wear resistance are more important than ductility or corrosion performance.