MMA electrodes

Often used when MMA electrodes and submerged-arc fluxes are dried at high temperatures, e.g. above about 250 °C, to remove moisture. When fluxes are dried at temperatures above about 800 °C the term pre-sintering is sometimes used. 

Heating of MMA electrodes or flux to remove moisture. The term is sometimes restricted to low temperature heating up to about 250 °C, which will remove only loosely bound water (see baking). 

An admixture of iron and other metal powders (alloying and/ or deoxidising) used either as an ingredient of MMA electrode coverings, or as an addition made during submerged-arc welding (see iron powder). 

The length of a weld bead deposited from the usable portion of a single MMA electrode, i.e. from the length of the electrode less 40 mm. 

The reciprocal of the run length (q.v.), i.e. the length of MMA electrode required to deposit unit length of weld bead and which is proportional to the heat input, divided by the square of the electrode core wire diameter. 

Gooch T G Repair welding (of hard to weld ferritic steels] with austenitic stainless steel MMA electrodes . Metal Constr 12 (llj 1980 622-677. 

Polystyrene is preferentially formed on the cathode surface. MMA cannot be incorporated until the styrene concentration at the electrode is reduced substantially during the course of the reaction. 

Figure 9-20. General sehematie of a plasma-ehemieal reae-tor for polymer film formation due to plasma-initiated ehain polymerization (1) glass reaetor (2) eooled substrate (3) cooling system (4) electrodes (5) discharge zone (6) inlet system for polymer-forming gases (for example, MMA and Ar) (6) pumping system.

Not every act of placing an electrode on the monolayer covered water surface resulted in making contact with the monolayer material. The probability of recording a voltammetric signal due to Ru(bpy)2(bpy-C19) oxidation depended inversely on the MMA of the ruthenium surfactant, and clearly reflected the fact that only a fraction of the water surface was covered with the solid aggregates of the compound. The authors proposed that experiments of this type, if done with electrodes of different surface areas, could be interpreted in terms of the average size of the 2D aggregates. 

The polymer used for this table was a PMMA-based side-chain polymer with DANS, with a molar ratio of DANS to MMA of 50 50. The contact electrode poling was performed at 140 C for 5 min with the poling field of 120 V//u,m, Photobleaching was performed by irradiation of UV light in an air atmosphere using a large-area illuminator [Oriel Co., 1000 W Hg(Xe) lamp] with a total intensity of 80 mW/cm for 15 h. 

Manual metal arc (MMA) or stick welding using a coated electrode manipulated manually... 

Table 2 Potential of the peak I for the electroreduction of MMA and AN depending on the electrode conductivity using various doped silicon as substrates...

Low-carbon unalloyed steels andlor low-alloyed steels. For thin-sec-tion, unalloyed materials, these materials can normally be readily welded. However, when welding thicker-section material with a flux process (MMA), there is a risk of HAZ cracking and low-hydrogen electrodes need to be used. The more highly alloyed materials also require preheat or a low-hydrogen welding process to avoid HAZ cracking. 

Ni Steels, CrMo, and CrMoV creep-resisting steel. Thin-section material may be welded without preheat, using a gas-shielded process (TIG and MIG) for thicker-section material, and when using a flux process, preheat with low-hydrogen electrodes (MMA) is needed to avoid HAZ and weld metal cracking. Postweld heat treatment is used to improve HAZ toughness. 

Design parts to give access to the joint area, for vision, electrodes, filler rods, cleaning, etc. MMA excellent for welds inaccessible by other methods. 

Methyl methacrylate (MMA) (7 g, M 120000) was dissolved in dry acetonitrile (70 g). LiC104 (3 g) was added to the solution as supporting electrolyte. Finally, PC (20 g) was added as plasticiser. The whole mixture was then slowly heated until gelation. The GPE was spread on the polymer-coated side of the electrode, and the electrodes were sandwiched under atmospheric conditions. 

The main welding process used to weld pipelines is the MMA method, manual welding with coated electrodes. There are many reasons for this choice. The first is the most obvious the manual electrode is the first product invented that is suitable for arc welding. 

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