OEM 61028391 | High Strength Class 10.9 | Direct Replacement

The OEM 61028391 Bolt, Hexagon is a high‑strength fastener manufactured for SANY heavy‑duty trucks and construction equipment. As genuine SANY parts, this bolt ensures proper clamping force in critical assemblies such as engine mounts, transmission flanges, and chassis connections. The part number 61028391 is produced from 40Cr alloy steel, heat‑treated to ISO 898‑1 Class 10.9. With a zinc flake coating, the 61028391 bolt withstands corrosion and vibration, extending maintenance intervals for SANY truck fleets. Every batch is tensile‑tested to guarantee reliability.

Bolt, Hexagon

Болт шестигранный

Perno Hexagonal

Material and Heat Treatment of 61028391 Hexagon Bolt

The 61028391 bolt is cold‑headed from 40Cr (AISI 5140) alloy steel. After heading, it undergoes quench and tempering to achieve a martensitic microstructure. The tensile strength of Hexagon Bolt consistently reaches 1040–1100 MPa, with yield strength above 940 MPa. Thread rolling after heat treatment creates a work‑hardened surface with residual compressive stress, improving fatigue resistance. This process makes the 61028391 bolt ideal for dynamic loading applications such as engine brackets and suspension links.

Hardness testing on every lot of Hexagon Bolt ensures Rockwell C 33–39, conforming to Class 10.9 requirements. The core hardness gradient is controlled to avoid brittleness while maintaining strength. Genuine 61028391 bolts are also tested for impact toughness at -40°C, guaranteeing performance in cold climates.

Technical Specifications of OEM 61028391

Applications of 61028391 in SANY Truck Models

The 61028391 bolt is factory‑installed on SANY SYM3250ZZX1E dump trucks, SYM4250T6 tractor heads, and SYM3310ZZX1E heavy haulers. Typical positions include front engine mount brackets, rear axle carrier flanges, fifth wheel coupling plates, and transmission housing bolts. SANY maintenance manuals list Hexagon Bolt as a mandatory replacement part whenever the engine or transmission is removed.

Additionally, Hexagon Bolt is used on exhaust manifold supports and turbocharger brackets for SANY‑DEUTZ diesel engines. For heavy haulage operations, using the correct 61028391 bolt eliminates risks of joint loosening caused by vibration. Many fleets stock Hexagon Bolt as a standard service kit item.

Why Genuine 61028391 Outperforms Aftermarket Bolts

Aftermarket bolts labelled Class 10.9 often use lower grade materials with inconsistent heat treatment. Genuine Hexagon Bolt is produced in ISO/TS 16949 certified plants, with full traceability from raw steel to finished part. The thread rolling process for Hexagon Bolt creates a smoother surface finish (Ra ≤ 1.6 µm) which reduces friction scatter. Counterfeit bolts may lack the required proof load, leading to thread stripping or fatigue failure under dynamic loads.

The zinc flake coating on genuine Hexagon Bolt is thickness‑controlled to 8–12 µm, ensuring consistent friction coefficient (µ = 0.12–0.16). Generic bolts often have excessive coating or poor adhesion, causing inaccurate torque readings and joint relaxation. Field data shows that using genuine 61028391 reduces bolted joint failures by over 60% compared to non‑genuine alternatives.

Installation Torque Guidelines for 61028391

To achieve correct clamp load, clean the bolt and tapped hole threads. Apply light engine oil to the threads and under the head of the 61028391 bolt. Hand‑start to avoid cross‑threading. Tighten in three steps: first to 70 Nm, then 140 Nm, and finally to 210 Nm ± 10 Nm using a calibrated torque wrench. For critical applications like connecting rods or main bearing caps, SANY advises torque‑to‑angle: after 70 Nm, rotate an additional 90°.

Never reuse a 61028391 bolt that has been torqued to yield. The fastener may have experienced plastic elongation. Always replace with a new genuine bolt. For suspension and chassis bolts, re‑torque after the first 500 km of operation when using a new Hexagon Bolt fastener.

Quality Assurance and Packaging of OEM 61028391

Each 61028391 bolt is individually sealed in a moisture‑proof polybag. Boxes contain 20 pieces with a label showing the OEM number, batch ID, torque specification, and QR code linking to the factory test certificate. SANY performs 100% dimensional inspection on thread profile, head height, and across‑flats dimension for every production lot of Hexagon Bolt. Additionally, random samples are pulled for tensile testing, hardness verification (HRC 33–39), and 720h salt spray test.

The 61028391 bolt meets DIN 931, ISO 4014, and SAE J429 Grade 8 standards. For bulk orders, SANY provides a certificate of conformance with shipment. By choosing genuine Hexagon Bolt, fleet managers avoid unplanned downtime and guarantee the safety of their heavy equipment.