The authors discover a new interesting generalized identity concerning differentiable functions via k–fractional integrals. By using the obtained identity as an auxiliary result, some new estimates with respect to Hermite–Hadamard–Fejér type inequalities via k–fractional integrals for a new class of function involving Raina's function, the so-called generalized (h 1 , h 2)–nonconvex are presented. These inequalities have some connections with known integral inequalities. Also, some new special cases are provided as well from main results.