EN 10204 Test certificate standards and types for welding consumables

Requirement of different EN certification for welding consumable is shown below:

Certificate Type

Title Summary of EN10204 requirements

Notes

2.1

Declaration of compliance with the order Statement of compliance with the order by the manufacturer No test results shown

2.2

Test report Statement of compliance with the order by the manufacturer based on non-specific inspections (tests) by the manufacturer. Like the old BS1449 ‘Cast Test’ certificate. Mechanical test sample results from another coil from same cast, manufactured by the same process route, can be used.

3.1

Inspection certificate Statement of compliance with the order by the manufacturer with results of specific inspection Common certificate type issued for ‘batch tested’ material. Cert. issued and signed by manufacturer’s representative, who must be independent of the manufacturing department. Eg Inspection department or test house manager/supervisor

3.2

Inspection certificate Statement of compliance with order with indication of results of specific inspection Batch test results. Cert. issued by both manufacturer’s representative and an independent inspector appointed either by the customer or an inspector designated by official regulations. This cover what is often referred to as ‘outside inspection’

When the 3.2 certificate type is requested the manufacturing mill may prepare a 3.1 type certificate to present to the ‘outside inspector’ to use as a basis for preparing the independent 3.2 certificate. Only the 3.2 certificate is valid however for the ordered requirements and to match the product marking and inspectors stamp.

Reference: Donghao stainless steel literature

Keep reading, Happy welding

KP Bhatt

 

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Things you must know about SMAW Electrode coatings!!!

A lot more depends on selection of the electrode type for successfully carrying out weld with SMAW process. Wrong selection of electrode type may lead to more defects, more repairs. The selection of correct type of electrode coating results in weld metal with desired quality characteristics at low cost. In general, welding electrode is selected in such a way that characteristics of weld metal are similar to or better than the base material while keeping in mind the welding position and weld joints design as they significantly affect the properties of the weld.

The covering of the stick electrode consists of a multitude of components which are mainly mineral, below figure shows coating raw material and its effect on the welding characteristics.

Capture1

Stick electrodes are, according to their covering compositions, categorized into four different types:

Cellulosic electrodes (Symbol C)

These electrodes are composed of large amount of hydrocarbon compounds and calcium carbonates besides other constituents and are found suitable for

  1. All welding positions especially for vertical and overhead welding position and
  2. Realizing high mechanical properties in a weld metal of radiographic quality.

These are preferred for vertical downward welding. However, these produce high hydrogen content in weld metal besides deep penetration.

Rutile electrode (Symbol R)

These electrodes predominantly contain rutile (TiO2) besides other constituents and are known to offer almost 100% weld metal recovery, easy arc striking and restriking. These are found suitable for

  1. Fillet welds,
  2. Welding of sheet metal,
  3. Good gap bridging capability,
  4. Free from spatter losses and
  5. All position welding.

These are recommended for welding low strength steel (<440 MPa). For welding of high strength steel (>440 MPa) generally weld metal should have low hydrogen level and therefore weld joints is developed using basic, rutile, basic-rutile and Zircon based electrode.

Basic electrode (Symbol B)

These electrodes have basic (alkali) coatings containing calcium carbonate / calcium fluoride. The basic electrodes are preferred over other electrode for developing weld joints of high strength steel (480-550 MPa) with weld metal having

  1. Low hydrogen,
  2. Good low temperature toughness,
  3. Resistance to hot and cold cracking.

However, these electrodes suffer from comparatively poor slag detachability. The welding speed and deposition rate offered by the basic electrodes especially in vertical welding position is much higher than the rutile and acidic electrode. Basic electrodes can sustain higher welding current even in vertical welding position.

Acidic electrode (Symbol A)

Coating

  1. Easier arc striking than basic electrodes but poorer arc striking than rutile electrodes,
  2. Moderate welding speed,
  3. Smooth weld bead
  4. Good slag detachability.

However, acidic electrode has been replaced by rutile electrode and basic electrode for flat and positional welding respectively. The ductility and toughness weld metal developed by acidic electrode are better than those developed from rutile electrodes however yield and ultimate tensile strength are found inferior. This type of electrode results in minimal penetration which is good for very thin sheet but these are sensitive to moisture pick up.

Below figure compares the characteristics of the four different types

Capture

Apart from these categories other type of coatings such as Iron powder coating electrode, basic-rutile electrode, etc.  are also available, which are basically general modifications of the four above mentioned categories to fetch more advantages by combining the positives of the each type.

Reference: Technical document, MMAW, Aachen, ISF & Technical document, Nptel

Keep reading, Happy welding,

Thank you

KP Bhatt