摘要:
Des terpolymères comprenant du propylène et de petites quantités d'éthylène et de butène-1 sont produits par un procédé en deux étapes. Un terpolymère aléatoire à point de fusion relativement élevé est obtenu pendant une première étape et un terpolymère aléatoire à point de fusion relativement bas présentant une teneur en éthylène plus élevée est produit pendant une deuxième étape de manière à être dispersé dans le produit de la première étape. Les deux étapes du traitement peuvent être exécutées dans un seul réacteur à charge discontinue ou dans deux réacteurs continus en série.
摘要:
Hot-dip aluminum-zinc coatings having an aluminum content in excess of about 25% aluminum exhibit a tendency for corrosion flaking, that is, selective corrosion along the interface between the aluminum-zinc overlay and the underlying intermetallic layer. The tendency to such corrosion flaking increases with the aluminum content of the coating. Methods for minimizing this tendency by accelerated cooling of the molten coating as it emerges from the coating bath are ineffective for coatings containing greater than 72% aluminum. It has been found that the addition of 0.04 to 0.32% magnesium in hot-dip aluminum-zinc coating baths will substantially enhance the resistance of the coating to corrosion flaking.
摘要:
Hot-dip coated steel articles having a coating containing about 55% aluminum, 43% zinc, 2% silicon, are known to exhibit an optimum combination of general corrosion resistance, more durable than zinc coatings; while providing more galvanic protection to cut edges and areas of mechanical damage than hot-dip aluminum coatings. It has now been found that coatings containing 12 to 24% zinc, up to 4% silicon, balance aluminum, provide galvanic protection equal to or superior to such known coatings, while providing enhanced general corrosion resistance, approaching that of aluminum coatings.
摘要:
In order to resist alteration of the spring forces utilized for applying seal pressure between the valve bodies in sliding gate valves for molten metal pouring, particularly those of the manually operated type, the valve support plate and the mounting plate are arranged to form a narrow slot that receives the valve actuator and presents insufficient clearance to permit excessive relative displacement between the valve members. The valve further incorporates releasable attachments, two of which serve as hinge connections for the support plate while the other serves as a latching member. Each of the attachments comprise clevis-mounted eyebolts in which the clevises have predetermined dimensions to establish a fixed, pre-set distance between the plates upon reassembly of the valve after opening and thus insure repeatability of the spatial relationships between the valve bodies and, concomitantly, of the seal pressure between the members.
摘要:
Carbonyl sulfide is removed from propylene by hydrolysis over a catalyst comprising platinum sulfide on alumina. When the hydrolysis is conducted in the gaseous phase, the catalyst is regenerated by contacting the catalyst with a solvent for polypropylene such as liquid propylene.
摘要:
Refractory anchoring for a layer (21) of refractory material to a refractory furnace lining (2) has a number of generally cylindrical refractory anchors (10) with a concave locking surface (16) on each end. Each anchor has one end cemented into a hole (18) in the lining and the other end covered with a cementitious refractory material (21). A plunger tool is used for inserting the anchor (10) and cement (20) into the hole (18) in the lining.
摘要:
High-strength, deep-drawable, steel sheet exhibiting dual-phase properties is produced by (i) initially annealing the sheet to achieve crystallographic textures yielding high deep drawability, (ii) heating the sheet to a temperature above the A, for a time sufficient to produce from 2 to 10% austenite, and thereafter (iii) rapidly cooling to transform at least a portion of the austenite to martensite or bainite. To achieve such transformation of austenite, the composition of the steel must be selected to provide a requisite degree of hardenability.