Diesel engines - Steel tubes for high-pressure fuel injection pipes - Part 1: Requirements for seamless cold-drawn single-wall tubes
1Key Takeaways
This document specifies the dimensions and requirements for high pressure seamless cold drawn single wall steel fuel injection pipes for use in diesel (compression ignition) engines (category 2) and for use in fuel injection pump testing (category 1). This document is applicable to diesel (compression ignition) engines…
2Expert Interpretation
An in-depth analysis of ISO 8535-1:2016, the professional technical specification for dimensional tolerances, mechanical properties, surface quality, and testing requirements for seamless cold-drawn single-wall steel tubes for diesel engine high-pressure fuel injection systems, covering key indicators such as material processing, cleanliness control, and pressure testing.
Analysis of the core requirements of the standard
ISO 8535-1:2016, sixth edition, proposes comprehensive technical requirements for seamless cold-drawn single-wall steel tubes for high-pressure fuel injection systems of diesel engines. The main updates include:
| Technical parameters | Class 1 (pump test) | Class 2 (engine) |
|---|---|---|
| Inner diameter tolerance (≤4mm) | ±0.05mm | ±0.025mm |
| Concentricity requirements | Proportional to wall thickness (see Figure 1) | |
| Mechanical property grade | Grade 6 (newly added Code5-6) | |
Materials and manufacturing process
Steel pipes must be made of non-alloy high-quality steel and must be heat treated after final diameter reduction to obtain the specified mechanical properties:
- Tensile strength range: 310-850N/mm²
- Vickers hardness upper limit: 340HV
- Inner surface roughness grading: S/O/P/Q/R five levels
Key test items
Pressure test case
Calculate the maximum test pressure according to the theoretical formula in Appendix A:
pmax = 103×(K2-1)/√(1+3K4)×ReH
Where K=D/d (diameter ratio), the typical value must be ≥2 and ≤4
Implementation Recommendations
- Give priority to size combinations with a diameter ratio of 2-4 (shaded cells in Table 1)
- Methanol fuel applications require zinc plating + colorless chromate treatment (Code 3)
- It is recommended to use internal surface quality control of P level (×200 magnification) or above