Func<int, bool> predicate = x => x == 5;
var items = Enumerable.Range(1, 5).Where(predicate);

var z = from o in viewOperations
                    join b in _buntRepository.Bunts on o.BuntCode equals b.Code
                    join s in _buntRepository.Steels on b.SteelCode equals s.Code
                    where (b.SteelCode == steelFilter || steelFilter == null)
                    group o by new { s, b.Diametr } into go
                    orderby go.Key.s.Name, go.Key.Diametr
                    select new SteelRawUse
                    {
                        Steel = go.Key.s,
                        Diametr = go.Key.Diametr,
                        Weight = go.Sum(x => x.Weight),
                        Count = go.Count()
                    };