Description
GB/T 3639 10# 20# 35# 45# Honed Hydraulic Cylinder Tubing
Material Description
GB/T 3639 specifies Honed Hydraulic Cylinder Tubing (grades 10#, 20#, 35#, 45#, 25Mn) used in hydraulic cylinders, mechanical systems, and automotive components.
Chemical Composition
Steel Grade | C (%) | Si (%) | Mn (%) | P (≤ %) | S (≤ %) | Notes |
---|---|---|---|---|---|---|
10# | 0.07–0.10 | 0.17–0.37 | 0.35–0.65 | 0.035 | 0.035 | Cu ≤ 0.20% for hot-press use |
20# | 0.17–0.23 | 0.17–0.37 | 0.35–0.65 | 0.035 | 0.035 | — |
35# | 0.32–0.39 | 0.17–0.37 | 0.50–0.80 | 0.035 | 0.035 | — |
45# | 0.42–0.50 | 0.17–0.37 | 0.50–0.80 | 0.035 | 0.035 | — |
Mechanical Properties
Grade | Condition | Tensile (MPa) | Yield (MPa) | Elongation (%) |
---|---|---|---|---|
10# | +C (BK) | ≥ 410 | — | ≥ 6 |
+LC (BKW) | ≥ 375 | — | ≥ 10 | |
+SR (BKS) | ≥ 335 | — | ≥ 12 | |
+A (GBK) | ≥ 335 | — | ≥ 24 | |
+N (NBK) | — | ≥ 205 | ≥ 24 | |
20# | +C | ≥ 510 | — | ≥ 5 |
+LC | ≥ 450 | — | ≥ 8 | |
+SR | ≥ 430 | — | ≥ 10 | |
+A | ≥ 390 | — | ≥ 20 | |
+N | — | ≥ 245 | ≥ 20 | |
35# | +C | ≥ 590 | — | ≥ 4 |
+LC | ≥ 550 | — | ≥ 6 | |
+SR | ≥ 520 | — | ≥ 8 | |
+A | ≥ 510 | — | ≥ 17 | |
+N | — | ≥ 315 | ≥ 17 | |
45# | +C | ≥ 645 | — | ≥ 4 |
+LC | ≥ 630 | — | ≥ 5 | |
+SR | ≥ 610 | — | ≥ 7 | |
+A | ≥ 590 | — | ≥ 14 | |
+N | — | ≥ 355 | ≥ 14 |
Execution Standard
Standard: GB/T 3639. Manufacturing: cold-drawn or cold-rolled. Delivery states include +C, +LC, +SR, +A, +N.
Applications
Extensively used for hydraulic cylinders, precision mechanical components, automotive parts; honed varieties (20# and 45#) serve aerial work platforms, agriculture, construction machinery, hydraulic jacks, etc.