Hydraulic Hammer
Hydraulic Hammer
a machine for working metal by blows from falling parts driven by fluid under high pressure. Hydraulic hammers are used for forging, closed-impression die forging, and sheet-metal stamping. They are similar in design to hammers utilizing other types of power—for example, steam hammers. Hydraulic hammers are not widely used because of the difficulty of controlling the impact force.
| Table 1. Properties of some hydraulic fluids | |||
|---|---|---|---|
| Viscosity at 50°C (m2 per sec) | Freezing point (°C) | Flash point (°C) | |
| *At 100°C | |||
| Hydraulic oil for automatic lines of metal-cutting lathes............... | (25-35) × 10−6 | -10 | 190 |
| Oil for presses............... | 1 × 10−7* | -15 | 200 |
| Oil for hydraulic drives of GT-50 diesel locomotives............... | (11-14) × 10−6 | -28 | 165 |
| Oil for motor vehicle hydraulic systems hydromechanical transmissions............... | (3.5-4) × 10−6* | -45 | 160 |
| torque converters and automatic gearboxes............... | (23-30) × 10−6 | -40 | 175 |
| power steering............... | (12-14) × 10−6 | -45 | 163 |
| Oil for high-load mechanisms (ESh)............... | 20 × 10−6 | -50 | 150 |
| Shock-absorber fluid (AZh-12T)............... | 12 × 10−6 | -55 | 165 |
| Hydraulic brake fluid (GTN oil)............... | 1 × 10−7 | -63 | 92 |
| Alcohol-glycerine fluids SG............... | 6.2 × 10−6 | -50 | 28 |
| SVG............... | 2.5 × 10−6 | -60 | 28 |
| SVG-2............... | 7.5 × 10−6 | -50 | 30 |
| Alcohol-castor oil fluids ESK............... | (8.2-8.6) × 10−6 | -25 | 12 |
| BSK............... | (9.6-13.8) × 10−4 | -25 | 14 |