Title

CURVAS TTT DE TRÊS AÇOS INOXIDÁVEIS SUPERMARTENSÍTICO MICROLIGADO AO BE, NB E TI

TTT CURVES OF THREE SUPERMARTENSITIC STAINLESS STEELS CONTAINING Be, Nb and Ti

Authorship

Rodrigues, C.A.D; Lorenzo, P. L. Di; Sokolowski, D. A.; Barbosa, B. C. A.; Rollo, J. M. D. A.

DOI

10.5151/2594-5327-0318

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Abstract

A nova classe de aços inoxidáveis Supemartensítico (Supermartensitic Stainless Steels-SMSS), recentemente desenvolvidos por a rota convencional de fundição a vácuo e tratamentos térmicos-mecânicos, apresentam melhorias nas propriedades de resistência mecânica, resistência à corrosão e soldabilidade, quando comparados aos aços inoxidáveis martensíticos comerciais. A instabilidade microestrutural destes aços está fortemente comprometida pela presença de altos teores de elementos de liga e da sua história térmica. Os aços SMSSS apresentam após tratamento térmico de têmpera e revenido uma porcentagem indesejável de ferrita-

 

In the evolution of stainless steel, a new class of materials has arisen, which are referred to as supermartensitic stainless steels (SMSS). They exhibit higher mechanical strength, corrosion resistance and weldability than the conventional martensite stainless steels. The instability microstrutural this SMSS to compressed strongly of the presence chemical content high alloys element and thermal history. The SMSS after quenching and tempered heat treatment present very small amount of ferrite unwanted. The work present continuos cooling transformations (CCT) and time-temperature-transformations (TTT) construction obtained transformations phase lines were to base information requisite the one good choice of thermal cycle for to utilize quenching and tempered heat treatment to development of SMSS with low Be, Nab and Ti, to rough state rolling. The microestrutural characterizations was accomplished using optical microscopy, scanning electron microscopy and using the dilatometer to realize isothermal treatment and continuous cooling. The TTT diagrams obtained shows the curve in C of initial transforamtions phase occurs rapid of range 170-230 second and terminal above 5000 of three stainless steels.

Keywords

Microestrutura; Dilatometria; Aços inoxidáveis Super-Martensítico; Berílio; Nióbio; Titânio; Transformação de fases em ligas ferrosas.

Supermartentic stainless steels, Stainless steels with Berryllium, Niobium, Titanium, Transformations of phases the alloys steel.