Dialogue with customers

Kharkiv Bearing Plant continues the communication with customers. Due to numerous requests from clients after the webinar: "Rules for mounting and operation of bearings. Reasons of failures" HARP publishes answers to the most exciting questions.

Vitaliy Poletaev, Head of the Product Development Department and leading technical specialist at HARP, provides answers to questions.

 

Does your factory have an End-User Service Department? How is the process of resolving issues with premature failure of bearings organized?

HARP service team is represented by an engineer for the application of bearing products and the OTK HARP (Technical Control Department) under the guidance of the HARP Quality Director. The process is organized as follows:

1. HARP receives a letter from the customer (it is better to sent directly by e-mail to otk@harp.ua or pvv@harp.ua)

2. OTK HARP prepares a response. If there is not enough data, the factory requests additional information:

* data sheet for HARP bearings (passport);

* description of the defect or non-compliance with GOST, ISO, DSTU, TU;

* photo materials: marking of the bearing, defect (if visible), the unit where the bearing worked;

* operating time of the machine (unit) at the time of failure;

· date of manufacture, sale, and commissioning of the equipment;

* warranty of the equipment manufacturer (warranty time).

3.      Manufacturers of equipment can conduct on-site expertise (upon agreement of the OTK HARP and the customer).

4.      It is possible to conduct research of samples sent by past at HARP (upon agreement of the HARP OTK and the customer).

5. Conclusion on failure is made on the basis of the received information.

 

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Procedure for investigating a failure of the unit equipped with HARP bearing.

In such cases, HARP takes the following steps:

1.      To identify the bearing manufacturer – marking, passport.

2.      To identify the bearing resource – speedometer readings, moto-hour counter, log entries (mounting, operation), acts of failure. Has the bearing fulfilled its warranty period?

3.      External inspection of the bearing and assembly for obvious damage. If necessary, measurements of mounting seats are made, verification of compliance with standard requirements for seats, analysis of possible failure factors (occurrence of an emergency situation during operation, loads unusual for the type of bearing used, etc.), and operating conditions.

4.      Inspection of internal damage in the bearing and the lubricant condition.

5.      If necessary, detailed analysis is performed, the laboratory analysis of the geometry of the outer and inner parts of the bearing, condition of the material (hardness, structure), internal damage, lubrication condition analysis after bearing disassembly.

6. Conclusion about the reasons of failure.

 

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What methods are used to control bearings when they are received from the supplier?

This issue is described quite well in clause 9 of GOST 520.

We would recommend that you first check the radial clearance, inner and outer diameter, and the hardness of the rings and rolling elements. 100% control is not necessary, 3-5 samples from the batch are enough (many measurements cannot be performed without disassembling the bearing). In critical cases, you can measure the vibration if you have a vibration stand, but you must inform the supplier what vibration class the bearing should correspond to. By default, serial bearings (and all brands) are not tested on the vibration stand during production, but at the customer's request, they are tested and assigned a vibration class (according to GOST – letter W (Sh) in the designation, for foreign manufacturers it is most often letter Q).

 

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Do you have hub bearings with ABS ring in your catalog? Do you only produce rolling bearings or friction bearings too?

We only produce hub bearings in standard size 256907 without an ABS ring. You can find information in the catalog – https://harp.ua/search/?search=catalog&q=256907&s=%D0%98%D1%81%D0%BA%D0%B0%D1%82%D1%8C

HARP produces rolling bearings, there are no sliding (friction) bearings in the range.

 

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About housed bearings: are bearing housings manufactured by your factory? Do you have your own foundry?

HARP does not have its own foundry. Housings are produced by several enterprises both abroad and in Ukraine. These are certified manufacturers, in particular in Ukraine – a major manufacturer of spare parts for cars and tractors. Some manufacturers have not passed the HARP tests and certification due to poor quality. We use only high-quality housings.

 

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What grade of cast iron is used in the manufacture of housed bearings? Are there any confirmed tests of other brands housings (FKL, SKF, FAG, NSK, etc.), i.e. how much do your housings correspond in chemical composition and strength to their analogues?

Standard HARP housings are made of grey cast iron of the SCh20 (GG20) grade.

At the moment, HARP ROCK high-strength bearing housings made of ductile cast iron VCh50 (GGG50) have already been manufactured and are being tested. HARP ROCK heavy-duty housed bearing units were developed in close cooperation with the largest European manufacturers of agricultural machinery in accordance with modern concepts of the world agricultural machinery industry. The equipment has to work in extreme conditions, quickly and effectively coping with heavy soils, high pollution and moisture, and withstanding super-strong shock loads.

This line will go on sale in the near future – see https://harp.ua/upload/iblock/122/leaflet_harp_rock_ru.pdf

Both grades of cast iron fully correspond to the specified analogues of other manufacturers both in chemical composition and strength. Moreover, we try to be better than analogues, so we offer bearings with unique seals, protection against turning the outer ring in the housing, and other design improvements – see https://harp.ua/upload/booklet/harp/presentations/webinar_2019.pdf

 

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Do you have a laboratory for testing cast bearing housings?

Yes, we have HARP test center, accredited by the NAAU (certificate no. 201336 dated 15.05.2019, valid until 11.12.2021). The test center controls the material grade, hardness, structure (metallographic analysis), geometric dimensions and roughness.

 

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Is it planned to enter new markets and apply new solutions for the agricultural sector, food, automotive and other industries in the context of the pandemic?

HARP actively develops a range of bearing products mainly in the agricultural and railway areas, these are historically established industries in which the plant operates. In these industries, there is an experimental base where we test our new products in the field, these are partner enterprises and operating organizations. For other industries (including automotive, heavy engineering, etc.), we try to maintain the range and quality of products already mastered, as well as adapt the serial production of HARP to the special requirements of the client (radial clearance, type of seals, lubricants). In the face of the pandemic, the plant has maintained the pace of production of bearings for various industries and markets. The key success factors for the company are still the stability of production and maintaining a high level of customer confidence. Therefore, in accordance with the signed contracts, HARP continues to ship products to partners and customers on a separately agreed schedule, including for export. During this time, no contracts were suspended or revoked.

In the context of quarantine restrictions, HARP is developing new forms of communication with customers: expanding the scope of online events to promote products in all priority markets-from design of online resources to conducting training webinars and technical consultations for the sales staff of the company's partners.