Superior Welding Performance Without Compromise: The New E 7018-1
Basic E 7018 electrodes have long been recommended for welding heavily loaded connections due to their high ductility and fantastic impact values. However, at lower operating temperatures the impact values decrease rapidly and 1% nickel is added to limit this decrease.
Certilas developed a completely new highly basic electrode without nickel that performs way better on 5 points.
A new development based on decades of experience, combined with the most modern production techniques, made it possible to develop a better product. The coating of basic electrodes consists largely of a mixture of CaF2 , SiO2 , FeO, Al2 O3 , TiO2 , MnO, CaO, K2 O and Na2 O.
The mixture of these minerals determines the degree of basicity from which the basic electrode derives its characteristics. The higher the basicity, the cleaner and more ductile the final weld will be. Over the years, thousands of recipes have been tried and it has been shown that each element influences both the welding arc and the final mechanical properties of the pure weld metal. For example, TiO2 contributes to a more stable arc but reduces the basicity and CaF2 ensures cleaning of the weld metal and a higher basicity.
The properties of all these elements is a whole science and that is also the best-kept secret. The trick is to improve certain properties without losing other beneficial properties.
- High impact toughness and high elongation
- Stable arc
- Easy restart
- Covering that does not crumble
- Covering that absorbs moisture less quickly
- Retention of impact toughness at low temperatures
- Good welding properties
- Low hydrogen <3ml
- Less spatter
- Improved welding characteristics in position
- Easy slag removal
The new CEWELD E 7018-1 derives its unsurpassed mechanical values from its high basicity, where normally the basicity is between 1.7 and 2.5 Boniszewski, the basicity of CEWELD E 7018-1 is far above 3. The impact toughness is therefore more than 100 joules at -40°C in combination with an extremely low hydrogen of <3 ml/100gr of weld metal.
Offshore applications generally have higher requirements for mechanical properties and DNV plays an important role in drawing up regulations and approving welding consumables. The minimum requirement for offshore applications starts at -40°C, but also sets requirements for the hydrogen content in the weld metal, with 5 ml per 100 grams being the maximum value.
CEWELD E 7018-1 (H4R) is also extremely suitable for PWHT applications due to its high basicity.
The addition of <1% Nickel has proven itself in offshore for a long time and was also necessary because there were simply no -40°C approved electrodes on the market. However, nickel also has some disadvantages. Nickel makes the weld pool more viscous, increases the yield strength and therefore also shows a significant decrease in elongation. In the welding properties we also see that the electrode is more sensitive to contamination.
The AWS A5.1 has many additional requirements that an electrode must meet, normally hydrogen values can only be achieved below 3 ml/100gr of weld metal if the electrodes are welded immediately after re-drying within 3 hours. Practice has shown that in offshore, usually in humid conditions, the maximum permissible values of 5 ml are already exceeded after 5 to 6 hours.
For this reason, basic electrodes are actually only supplied in vacuum packaging to gain more certainty about the hydrogen present. H4R (Hydrogen <4 Resistant) is a higher classification where it must be demonstrated that the electrodes are less hygroscopic and that after 9 hours of exposure to 80% humidity at 36°C still a deposit with a hydrogen content below 5ml/100gr. can produce.
The “M” classification is a military classification that places even higher demands on the hydrogen percentage directly from the packaging and also requires higher notch toughness.
Latest vacuum packaging
At Certilas, the electrodes are vacuum packed fully automatically in a temperature controlled room and provided with a special 4-layer nylon reinforced foil.
✔ The highest impact values
✔ The highest elongation
✔ The highest ductility
✔ The best welding properties
✔ The lowest possible moisture absorption
Would you like to experience the highest quality basic electrode with your own eyes in your own circumstances?
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