Hydraulic Cylinders - ISMT Limited
Tubes for Hydraulic Cylinders
ISMT Limited has developed a range of specialized tubes for the manufacture of hydraulic cylinders. The steel used for the manufacture of these tubes is produced inhouse. The steel is produced through the electric arc furnace route, is fully killed and vacuum degassed ensuring a very low inclusion rating. As a result, cylinders produced from these tubes have a blemish free surface finish and a longer service life. Furthermore, these tubes are produced through the Assel Mill route resulting in very tight dimensional tolerances thus minimizing the requirement for final machining.
Depending on the finishing operation to be used by the customer for producing the cylinder, ISMT Limited supplies hydraulic cylinder tubes in three different categories (Type I, Type II, Type III). These categories are distinguished not only by the dimensional tolerances of the tubes but also by the excess material left for the finishing operation. Within each of these categories, tubes can be supplied from four standardized grades of steel. Alternatively, the company can make tubes from a customized grade of steel to meet the specific requirements of a customer.
Steel Grade
| Steel Grade | Chemical Composition (in %)** | |||||||
| C | Mn | Si | S | P | Cr | Ni | V | |
| ISMT HM1 | 0.18 to 0.21 | 1.25 to 1.35 | 0.10 to 0.35 | 0.025 max | 0.025 max | - | - | - |
| ISMT C5 | 0.22 to 0.28 | 0.70 to 0.90 | 0.10 to 0.35 | 0.025 max | 0.025 max | - | - | - |
| ISMT C8 | 0.37 to 0.42 | 0.60 to 0.90 | 0.10 to 0.35 | 0.025 max | 0.025 max | - | - | - |
| ISMT HM3 | 0.16 to 0.22 | 1.40 to 1.80 | 0.10 to 0.35 | 0.025 max | 0.025 max | 0.15 max | 0.30 to 0.50 | 0.12 to 0.18 |
**Note : "S" can be controlled within 0.020 to 0.035% for better machinability if needed.
| Steel Grade | Type | Tensile Properties (Min) | ||
| TS kg/mm2 | UTS kg/mm2 | Elongation | ||
| ISMT HM1 | Type 1 & 2 Type 3 |
52 36 |
61 52 |
15 22 |
| ISMT C5 | Type 1 & 2 Type 3 |
52 30 |
61 48 |
15 24 |
| ISMT C8 | Type 1 & 2 Type 3 |
60 39 |
70 60 |
15 18 |
| ISMT HM1 | Type 1 & 2 Type 3 |
65 46 |
75 58 |
12 15 |
Microstructure
Microstructure consists of grains of pearlite & ferrite. Grain size is checked in accordance to ASTM E112 and is No. 5 or finer. The inclusion rating is conducted in accordance to ASTM and is guaranteed to be better than 2.5A, 1.5C & 1.5D thick & thin series. Tube bore is free from isolated inclusions, which could leave pinholes after brushing or honing the inner diameter.
Lengths
Tubes are supplied in cut to length pieces (max 6 meters), as per customers specification, with a tolerance of (+5, -0)mm.