Showing papers on "Maraging steel published in 1968"
TL;DR: In this article, the fracture, mechanical properties, stress corrosion and composition relations for maraging steel are reviewed, and a detailed review of fracture and mechanical properties of steel is presented.
Abstract: : Reviews fracture, mechanical properties, stress corrosion and composition relations for maraging steel.
74 citations
TL;DR: In this article, the effects of moisture and hydrogen on the rates of fatigue-crack propagation and on the fracture path through the microstructure of 18Ni(250) maraging steel were examined at room temperature in dry and humid argon and hydrogen environments.
39 citations
TL;DR: In this article, an analytical model was developed for the elastic-ideally plastic behavior of concentric cylindrical composites under uniaxial tension, which predicted the creation of transverse stresses in the composite during axial loading.
Abstract: An analytical model was developed for the elastic-ideally plastic behavior of concentric cylindrical composites under uniaxial tension. The model predicted the creation of transverse stresses in the composite during axial loading. The existence of these stresses was experimentally verified in a 4140 steel core-18% Ni maraging steel case composite system by examining the effects of the trans verse stresses on the composite axial stress-strain curve and the composite tangential surface strain ratio curve.
23 citations
TL;DR: The α→γ transformation in steel N18K9M5T occurs on holding at 500-730°C or on heating at rates below 30-50 deg/sec by way of martensite decomposition in the two-phase α+γ region with redistribution of alloying elements between ferrite and austenite.
Abstract: 1.
The α→γ transformation in steel N18K9M5T occurs on holding at 500–730°C or on heating at rates below 30–50 deg/sec by way of martensite decomposition in the two-phase α+γ region with redistribution of alloying elements between ferrite and austenite.
2.
The main reason for the stable austenite formed on holding in the α→γ temperature range is the redistribution of alloying elements (enrichment of austenite in nickel).
3.
The rate at which martensite decomposes is very high, and therefore during heating to quenching temperature or during welding there is always formed some stable austenite enriched in nickel, which leads to residual austenite in the structure. The amount of residual austenite can be reduced by homogenizing annealing for 30–60 min at 820°C.
5 citations
2 citations
TL;DR: The strength of light melts can be increased substantially by increasing the aging time to 16 h at 450°C without lowering the plasticity as discussed by the authors, and the ductility of the unaged steel is somewhat higher than that of the overaged steel.
Abstract: 1.
Grain refining of overheated steel 00N18K9M5T requires triple water-quench or air-quench from 900–950°C (holding 1h) before quenching from 820°C.
2.
For the same strength, the ductility of the unaged steel is somewhat higher than that of the overaged steel.
3.
The strength of “light” melts can be increased substantially by increasing the aging time to 16 h at 450°C without lowering the plasticity.
2 citations
2 citations
01 Jan 1968
TL;DR: Plane strain fracture toughness tests on two inch thick maraging steel plate at various strength levels were conducted by as discussed by the authors, and the results showed that the steel plate was robust to strain fracture at different strength levels.
Abstract: Plane strain fracture toughness tests on two inch thick maraging steel plate at various strength levels
2 citations
TL;DR: A strength of more than 200 kg/mm2 can be obtained in commercial melts of MS 200 steel with satisfactory plasticity (δ=8-10% in forged bars and 4-5% in plates) by air quenching from 820°C and aging 4-6 h at 480-500°C as mentioned in this paper.
Abstract: 1.
A strength of more than 200 kg/mm2 can be obtained in commercial melts of MS 200 steel with satisfactory plasticity (δ=8–10% in forged bars and 4–5% in plates).
2.
MS 200 steel is considerably less susceptible to brittle fracture than other high-stength steels.
3.
The optimal mechanical properties of MS 200 steel are obtained by air quenching from 820°C and aging 4–6 h at 480–500°C.
4.
Reducing operations must be completed at temperatures of 900–850°C.
5.
High mechanical properties can be obtained in maraging steels free of impurities and gases.
1 citations
01 Oct 1968
TL;DR: In this article, a three-phase program concerns processes for the manufacture of thin extruded, drawn, and heat treated tee shapes, and the results of phase I show a relationship between alloy content, extrudability, and ram speed.
Abstract: : The three-phase program concerns processes for the manufacture of thin extruded, drawn, and heat treated tee shapes. In phase I, a production manufacturing process for the extrusion of 0.062-inch-thick by 20-foot-long tee shapes in AISI 4340, PH 14-8 Mo, and 18% Ni maraging steel was provided using a 1,200-ton Hydropress. The extrusion procedures, glass lubrication, temperature, and post-extrusion thermal and mechanical property tests are described. The results of Phase I show a relationship between alloy content, extrudability, and ram speed. AISI 4340 is the easiest to extrude and has the highest ram speed of the three alloys extruded. 18% Ni maraging steel is the most difficult to extrude and has the lowest ram speed during extrusion. The ram speed and extrudability of PH 14-8 Mo is between the two. A reproducible drawing process was refined in Phase II to reduce the thickness of the 20-foot-long tee extrusions to a target thickness of 0.040 inch. The success of the drawing phase of the program is primarily attributed to the invention of an adjustable draw die system that completely eliminates the necessity for 'pointing.' A process to heat treat 20-foot-long by 0.040-inch-thick extruded and drawn AISI 4340, PH 14- 8 Mo, and 18% maraging steel tee shapes was in Phase III. The heat treat response of the three alloys is adequate and exceeds the target mechanical properties for AISI 4340 and PH 14-8 Mo.
15 Oct 1968
TL;DR: The 400 Ksi yield grade was chosen as the first steel of this group for production development as mentioned in this paper, and the composition and phases present in this ultra high strength steel are discussed.
Abstract: : In the relatively short span of about 10 years maraging steels were conceived and developed into highly respected engineering alloys. This type of steel has not reached its full strength potential and this presentation details the evolution of the latest production maraging steel; a 400 Ksi yield grade. This steel is a member of a new compositional group which has demonstrated yield strength capability in excess of 500 Ksi in the laboratory. The 400 Ksi yield grade was chosen as the first steel of this group for production development. The composition and phases present in this ultra high strength steel are discussed. Mechanical properties and structures of wrought bar made from 15 pound laboratory vacuum induction melts are compared with those of bar stock made from a 16-inch vacuum arc remelted ingot weighing more than 2000 pounds. The influence of thermal treatments upon properties and structure is discussed in relation to the fabrication of finished parts made from the production melted 400 Ksi yield maraging steel.
01 Jun 1968