A Columbia man convicted of child abuse and battery for severely scalding his 4-year-old stepson in a shower and at an outdoor barbecue pit was sentenced yesterday to serve 18 months in the Montgomery County jail.

Montgomery County Circuit Court Judge Vincent E. Ferretti imposed the sentence on Scott E. Hyre, 26, before a visibly upset prosecutor and county child welfare officials. Ferretti said he was "not going to be as cruel" to Hyre as Hyre had been to the child.

Hyre and his wife, Laurie L. Hyre, 28, will be incarcerated for the same length of time, though Scott Hyre was convicted of the more serious charge of child abuse. It is punishable by up to 15 years in prison.

On Nov. 9, Laurie Hyre was sentenced for failing to intercede when her husband forced the boy to stay in front of a barbecue pit in June 1989 as punishment because the child refused to count to 10. The boy suffered second-degree burns on his legs and thighs, police said.

Yesterday, Ferretti, who appeared anguished about the sentence, condemned Scott Hyre's actions and his failure to take responsibility for the child's injuries.

"I don't think you are an evil person," Ferretti said. "What you did to this child is evil. You have not owned up to the reality to this case."

Ferretti said he was concerned about appropriate psychological counseling and medical treatment for Hyre's serious diabetic condition in the state prison system.

In a rambling statement, Hyre attributed a large part of his troubles to diabetes, which has resulted in blindness in his right eye and other medical complications. Hyre said he was sorry for the scalding incidents. "It was a terrible thing that happened."

Prosecutor Constance Junghans asked for a stiff sentence for Hyre's "depraved" and "sadistic" behavior. "Hyre robbed this boy of his childhood. The cruelty will affect him for the rest of his life."