Production Tolerancies

In case of the Heads one of the most important parameters is the minimal tolerance of the thickness. In case the order refers to standardized Heads ( i.e. DIN 28011, DIN 28013, etc.) means that the minimum thickness is determined by the standard.
Further sizes which are generally determined by tolerancies:

  • height

  • circumference measured on the edge

  • ovality and conicity of the cylindrical part

In case of non-standardized products these tolerances should be given when the order is placed. Also an agreement is needed in case of special surface requirements or of eventual quantity limitation.

Heat treatment

Heat treatment technology of the Heads are determined according to the regulation of the production code applied ( i.e. AD 2000 Merkblatt HP7) or formed by the customer's demand. The aim of the heat treatment procedures is generally to restore or normalize the contexture which has formerly been hardened during the cold-forming process.
The embordering sizes of our furnaces make us possible to get through with post- heat treatmet at  almoust all of the articles produced. Nevertheless a number of test results confirm and the quality controll system applied guarantees that the pressing technology results proper normalized condition and thus the the post-heat treatment is not necessary.

Edge preparation

The edges of the Heads should be prepared due to the welding process required to be applied. The way of edge-preparation should be fixed upon receipt of the order. Thereto we normally use the markings of the point 2.2 of the standards DIN 28011 and DIN 28013 ( Editions of January 1993). The most frequent ways of edge executions are:

  • rough (code R)

  • plain (code I)

  • V-edge outside 30°(code VA)

Of course it is also possible to place orders for non-series edge-preparations. Joggled edge is a frequently used edge execution at the  heads with/under thickness 10 mm which is very advantageous due to its fast assembling feature mainly at the heads are to be produced in quantity.

Surface treatment

All the requirements to the surface of the Heads should be fixed upon receipt of the purchase order. For lack of any requirements the surfcace is to be considered as untreated (raw). For sand blasting there are two technologies at our disposal:

  • technology of rolling - scattering on block-chain run

  • technology of scattering room with free spout - scattering

In case of surface requirements incrased we complete burnishing. Picling and then passivating are the proper surface treatments of  the products are made of stainless steel.

Name examples

DIN 28011 - 1500 x 6 - I - P265 GH (EN 10028-2)
Torispherical head acc. to DIN 28011: outer dimeter 1500 mm; nominal thickness 6 mm (min. 5,7 mm) edge preparation: square edge (I); materialquality P265 GH

DIN 28013 - 1500 x 7,2 MIN - VA - P265 GH (EN 10028-2)
Semi-ellipsoidal head acc. to DIN 28013: outer dimeter 1500 mm; minimal thickness 7,2 mm edge preparation: V-Edge outside 30o (VA); Materialquality P265GH

NORMAL - 2500(r80) x 7 K - R - S235 JRG2 (EN 10025)
Standard-type head: outer diameter 2500mm; small radius 80 mm; starting thickness 7 mm egde unprepared; materialquality S235 JRG2

Required information for offering a tank head

  1. Form (standard definition): S - torispherical; M - semi-ellipsoidal; N - standard-type; P - ellipsoidal; etc.

  2. Main dimensions (ØD x s): D - diameter, it can be outer diameter or inner diameter (ID); s -
    thickness, it can be nominal (N), starting (K), or minimum (M)

  3. Height dimensions: (h1, h3)

  4. Materialquality: EN 10025; EN 10028-2; EN 10028-3; EN 10028-7; etc. (In case of a hot-dip galvanized product, please specify the requirements regarding the Si-content!)

  5. Material provider: Technokov Kft. or the Orderer. (In case the Orderer provides the material,
    please have respect to the relevant regulations of our General Contractual Conditions.)

  6. Welding: not allowed or allowed; welding technology according to customer's demands or by the technology of Technokov.

  7. Testing the weld: visual test (VT); liquid-penetrant inspection (PT); magnetic particle
    examination (MT); X-ray test (RT); ultrasonic test (UT). The extent of the test must be specified in %, and the requirements regarding the evaluation also has to be specified.

  8. Forming method: cold, hot, or defined by Technokov Kft.

  9. Heat-treatment: normalization; stress relieving; austenisation, or defined by Technokov Kft.

  10. Edge preparation: edge unprepared (R); square (I); V-edge outside 30º (VA); etc. (see under).

  11. Mechanical tests: no customer's prescription; Impact test at … ºC; Tensile test; Hot-tensile test at … ºC; Intercrystalline corrosion test; Other.

  12. Certification: EN 10204:2005-2.2; EN 10204:2005-2.3; EN 10204:2005-3.1; EN 10204:2005-3.2; EN 10204:2005-3.1+ AD2000; EN 10204/2005-3.2 + AD2000; EN 10204:2005-3.1 + PED; EN 10204:2005-3.2 + PED; Other