Hot-salt corrosion of alloys PT-7M, 42ХНМ, Inconel 690, Incoloy 800

Oleg Bykh,А В Ершова ,Н Г Сандлер ,Е В Логинова ,P V Tryaev ,А С Михайлов ,А М Бахметьев ,Aleksey Sozinov

doi:10.1051/e3sconf/201912104015

Oleg Bykh, А В Ершова + Show 6 more

Open Access

https://doi.org/10.1051/e3sconf/201912104015

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Abstract

The Article contains the results of the study performed for the samples made from alloys PT-7М, 42ХНМ, Inconel 690, Incoloy 800 for resistance against hot salt corrosion in the mixture of crystallized NaCl and KBr salts, in ratio 300:1 by weight, and in the temperature range from 150 °С to 300 °С, both in contact with the air and in a leak-tight autoclave in the atmosphere of saturated water steam. Regularities of hot salt corrosion behavior in the alloys under the study were detected under testing conditions. The atmosphere of saturated water steam inhibits development of halt salt corrosion of alloy ПТ-7М in the entire temperature range of the testing.

Highlights

1 Introduction This study was carried out to evaluate hot-salt corrosion resistance of the tube samples made of PT-7M, 42ХНМ, Inconel 690, and Incoloy 800 alloys upon contact with crystalline chlorides and alkali metal bromides in the temperature range from 150 °С to 300 °С, which is typical for heat-exchange equipment operation
Titanium alloys used in heat-exchange equipment are exposed to hot-salt corrosion in the aforementioned salts provided that the appropriate conditions take place [1]
Titanium and titanium alloy oxide film reacts with crystalline salts and water forming sodium titanate (Na2TiO3) and hydrogen chloride (HCl) which further reacts with titanium in (2) as follows: Тi + 4HCl →

Summary

Introduction

This study was carried out to evaluate hot-salt corrosion resistance of the tube samples made of PT-7M, 42ХНМ, Inconel 690, and Incoloy 800 alloys upon contact with crystalline chlorides and alkali metal bromides in the temperature range from 150 °С to 300 °С, which is typical for heat-exchange equipment operation. Titanium alloys used in heat-exchange equipment are exposed to hot-salt corrosion in the aforementioned salts provided that the appropriate conditions take place [1]

Mechanism of hot salt corrosion of titanium alloys

Materials and procedure of the studies

Results of comparative corrosion testing of samples

Conclusion