Effect of heat treatment on the properties of deformed alloy 36N

Abstract

Iron-nickel alloy 36N (Invar) is widely used in industry as a material having an anomalously low and almost constant thermal coefficient of linear expansion (TCLE) in the temperature range of 20 -100°C. This value of the coefficient is attained after heat treatment of the deformed semifinished product by the regime of quenching from 830°C in water, tempering at 315°C for I h, and aging at 95°C for 48 h. The minimum value of the TCLE is provided by the quenching operation, whereas the tempering and aging prevent growth of the TCLE during long-term operation of lnvar. The use of such heat treatment for rods and wire of alloy 36N guarantees a TCLE ofat most 1.5 x 10-6 °C-~. It is known that the value of the TCLE and the level ofthe mechanical properties of lnvar can be changed by changing the temperature and deformation regime of its treatment. The aim of the present work is to determine an optimum regime of heat treatment of the alloy after drawing that would ensure, without a finishing treatment, a TCLE not exceeding 1.0 x 10 -6 °C-I in the temperature range 20 -100°C.Some data on the properties and heat treatment of alloy 36N can be found in the reference books [i, 2].Our experiments were conducted on rods 9.05 mm in diameter produced by hot rolling and wire 5.02 and 2.56 mm in diameter made of lnvar having the following composition: 35% Ni, 0.03% C, 0.54% Mn, 0.03% Cr, 0.28% Si, 0.015% S, 0.013% P.The wire was produced by cold drawing from rods 9.05 mm in diameter on a VS 1/550 drawing mill at a drawing rate

Hydraulic Press Open Die Forging of 21CrMoV5-7 Steel CCM Roller with Flat Upper and Concave Semi-round Lower Cogging Dies

“…Material's uniformity improvement and increase at the treatment using increasing or complicating the tools set can be justified economically only for forging ingots made of high alloy steels or rare metals [27]. To equal the mechanical properties over the product cross-section, deformation schedules are combined directly [28] or stepped [29] heat treatment. However, investigations described in [30] deserve attention.…”

Effect of Particular Combinations of Quenching, Tempering and Carburization on Abrasive Wear of Low-Carbon Manganese Steels with Metastable Austenite

“…It is 1.7 times higher than that of steel 110G13L. High tempering at 650°C destabilizes austenite due to carbide formation and, accordingly, depletion of austenite by carbon [9][10][11][12][13][14][15][16][17]. This intensifies the formation of strain-induced martensite, the increase in its amount on the surface wear and causes an increase in abrasive and a decrease in shock-abrasive wear resistance.…”

Analysis of Galvanized Steel Sheets Fabrication in Cold Rolling Shop and Identification of Local Impacts Contributing to Corrosion of Metal-Products

“…has a significant impact on the occurrence and development of corrosion processes for products from galvanized steel. Namely [1,8,14]: thoroughness of descaling of the initial hot-rolled coils, subject to further pickling and washing off the acid from the surface of steel coils using organic emulsions, the strength of the applied zinc coating, its ability to deform together with the base sheet metal without cracking and delamination, absence of scoring and scratches during transportation and movement of the strip along the roller table, in rolls, knives and other devices, etc.…”