NZW-20 N·m Metal Rotating Beam Fatigue Testing Machine (RR Moore Type)

The CHENJI NZW-20 N·m metal rotating beam fatigue testing machine determines the fatigue limit and fatigue life of round and flat metal specimens under constant-amplitude rotating bending load, following the rotating-beam (RR Moore) test principle. It applies a pure four-point rotating bending moment to the specimen through dead-weight loading: as the specimen rotates at the selected speed every point on its surface experiences a fully reversed sinusoidal stress cycle, from which the S-N curve and fatigue limit are obtained.

The rotating beam test is the classic way to measure the fatigue strength of a metal, because it produces a fully reversed stress cycle with a simple, accurate machine. The NZW-20 adds stepless rotation-speed control and automatic cycle counting with power-off memory, so a test that runs for millions of cycles can be left unattended and resumed safely if the power is interrupted.

Technical Specifications

Four-point rotating bending and load accuracy

The machine applies a pure four-point rotating bending moment through dead-weight loading, which gives a uniform bending moment in the gauge section and a well-defined stress at the surface. Because the load is set by weights rather than by a spring or a screw, the bending moment stays accurate and repeatable for the whole test. The specimen shank is held in an ER collet for diameters from 1 mm to 20 mm, with a specimen length of 90 mm to 220 mm, and the gauge diameter is prepared per ISO 1143 or as required. ISO 1143 and GB/T 4337 cover rotating bar bending fatigue testing, which is how the NZW-20’s results are made comparable with other laboratories.

Stepless speed and automatic counting

The rotation speed is steplessly adjustable from 1000 r/min to 9000 r/min, so the operator can choose a faster speed to shorten a long test or a slower speed where heating of the specimen would affect the result – at 6000 rpm the specimen sees approximately 100 Hz. Cycle counting is automatic and the count is retained when the power is switched off, so an interruption does not destroy a test that has already run for millions of cycles; the machine stops automatically when the preset number of cycles is reached. It runs from an ordinary single-phase AC 220 V, 50 Hz supply.

Applications

The NZW-20 is widely used in metal-materials research, heat-treatment quality control, spring-steel and rolling-bearing material evaluation, and mechanical-component fatigue-testing laboratories. It is used to build S-N curves, to determine the fatigue limit of a material, to compare the fatigue strength of different heats or heat treatments, and to support failure analysis when a rotating part such as a shaft or spring has failed in service.

Frequently Asked Questions

What does the NZW-20 rotating beam fatigue machine test?
It determines the fatigue limit and fatigue life of round and flat metal specimens under constant-amplitude rotating bending load, following the rotating-beam (RR Moore) test principle, from which the S-N curve is built.

How does the machine apply the load?
It applies a pure four-point rotating bending moment through dead-weight loading, so the bending moment in the gauge section is uniform and the reversed stress at the surface is well defined.

What specimen sizes does the NZW-20 accept?
The specimen shank diameter is 1-20 mm, held in an ER collet, with a specimen length of 90-220 mm. The gauge diameter is prepared per ISO 1143 or as required.

What speed range and counting features does it have?
Rotation speed is steplessly adjustable from 1000 r/min to 9000 r/min. Counting is automatic, the count is retained on power-off, and the machine stops automatically at the preset number of cycles.

Which standard covers the rotating beam fatigue test?
ISO 1143 and GB/T 4337 cover rotating bar bending fatigue testing, so results from the NZW-20 are comparable with other laboratories that follow the same method.

Related Products & Pages

• Fatigue Testing Machines
• Rubber Fatigue Testing Machine
• High Temperature Fatigue Testing Machine
• Metal Testing Machines

About CHENJI & Support

CHENJI is the brand of Jinan Chenji International Trade Co., Ltd. (Shandong, China), a manufacturer and exporter of material testing machines since 2014, with in-house quality control plus third-party inspection by SGS or Bureau Veritas. The company holds ISO 9001 certification (626024QH073R1) and is a Bureau Veritas audited supplier (MIC-ASR2451820). Testing machines are normally supplied with a calibration certificate valid for 12 months and traceable to national force standards, and our engineers help you select the machine, fixtures and accessories for your specimen and method.

Every quotation is prepared against the standard you test to, so the delivered machine matches the test method rather than only the headline capacity. Spare parts, consumables and calibration support are available after delivery, and machines can be produced to OEM or ODM requirements when a customer drawing or specification is provided.

Selecting and Verifying a Testing Machine

Choosing a machine is a matter of matching capacity to the specimen and the method, not of buying the largest frame. A 1000 kN machine is not suitable for a sample that needs 1 N of force; capacity selection follows the specimen and the standard, and the force measuring system should be verified per ISO 7500-1 or ASTM E4 on a regular schedule. Load cells are commonly supplied as class 0.5 or class 1, which means the indicated force stays within ±0.5% or ±1% of the true force.

Test results are only comparable when they are quoted together with the standard, the specimen geometry, the test speed and the force measurement class. We are glad to review your test method and specimen so that the machine, fixtures and accessories are correctly specified before you order.

Request a Quotation

Tell CHENJI the material, specimen diameter and cycle range you need, and we will confirm the NZW-20 rotating beam fatigue machine and price for a quotation.

Email annie@chenjitester.com or call / WhatsApp +86 158 5311 1612.